Remove #ifdef and error handling

Fixes: poppler/poppler#1412

Fixes #1395

Hopefully fixes #1408

Rectangle corrections by Marek Kasik

Fixes KDE Bug #471422

When overprint preview is enabled, the image data row size changes
during conversion to XBGR. The Qt bindings were assuming this row
size was constant which led to badly broken QImages at conversion
time (generating garbage if displayed or even crashing).

This commit simply add regression tests for the case and gets the
row size after bitmap conversion.

Document how the backends interacts with the OCSP and AIA flags,
and ensure the implementation matches.

This simplifies the code, and saves a few heap allocations.

Rather than as a pointer to a GooString

Safer and simpler code, and less memory allocations.

Rather than storing a pointer and allocating the std::vector
on the heap.

This simplifies the code and saves a few heap allocations.

Fixes a regression introduced by recent
9183da4f commit which caused the
following Valgrind error:

```
$ valgrind utils/pdftoppm /tmp/test.pdf
==3735668== Memcheck, a memory error detector
==3735668== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==3735668== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==3735668== Command: utils/pdftoppm /tmp/test.pdf
==3735668==
Syntax Warning: May not be a PDF file (continuing anyway)
Syntax Error: Unterminated string
==3735668== Invalid write of size 2
==3735668==    at 0x4A3570C: utf8ToUtf16(char const*, unsigned short*, int, int) (poppler/UTF.cc:353)
==3735668==    by 0x4A3584C: utf8ToUtf16(char const*, int*) (poppler/UTF.cc:368)
==3735668==    by 0x4A358D4: utf8ToUtf16WithBom(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (poppler/UTF.cc:379)
==3735668==    by 0x49F2C97: Lexer::getObj(int) (poppler/Lexer.cc:424)
==3735668==    by 0x4A035C2: Parser::Parser(XRef*, Stream*, bool) (poppler/Parser.cc:50)
==3735668==    by 0x49F888B: Linearization::Linearization(BaseStream*) (poppler/Linearization.cc:28)
==3735668==    by 0x4A06D8D: getLinearization (poppler/PDFDoc.cc:648)
==3735668==    by 0x4A06D8D: PDFDoc::isLinearized(bool) (poppler/PDFDoc.cc:700)
==3735668==    by 0x4A0518D: PDFDoc::getStartXRef(bool) (poppler/PDFDoc.cc:2003)
==3735668==    by 0x4A04BB8: PDFDoc::setup(std::optional<GooString> const&, std::optional<GooString> const&, std::function<void ()> const&) (poppler/PDFDoc.cc:246)
==3735668==    by 0x4A04AAB: PDFDoc::PDFDoc(std::unique_ptr<GooString, std::default_delete<GooString> >&&, std::optional<GooString> const&, std::optional<GooString> const&, void*, std::function<void ()> const&) (poppler/PDFDoc.cc:160)
==3735668==    by 0x49F93EA: LocalPDFDocBuilder::buildPDFDoc(GooString const&, std::optional<GooString> const&, std::optional<GooString> const&, void*) (poppler/LocalPDFDocBuilder.cc:0)
==3735668==    by 0x4A1FBB5: PDFDocFactory::createPDFDoc(GooString const&, std::optional<GooString> const&, std::optional<GooString> const&, void*) (poppler/PDFDocFactory.cc:62)
==3735668==  Address 0x669cf54 is 0 bytes after a block of size 148 alloc'd
==3735668==    at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==3735668==    by 0x4A35815: gmalloc (goo/gmem.h:44)
==3735668==    by 0x4A35815: gmallocn (goo/gmem.h:121)
==3735668==    by 0x4A35815: utf8ToUtf16(char const*, int*) (poppler/UTF.cc:367)
==3735668==    by 0x4A358D4: utf8ToUtf16WithBom(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) (poppler/UTF.cc:379)
==3735668==    by 0x49F2C97: Lexer::getObj(int) (poppler/Lexer.cc:424)
==3735668==    by 0x4A035C2: Parser::Parser(XRef*, Stream*, bool) (poppler/Parser.cc:50)
==3735668==    by 0x49F888B: Linearization::Linearization(BaseStream*) (poppler/Linearization.cc:28)
==3735668==    by 0x4A06D8D: getLinearization (poppler/PDFDoc.cc:648)
==3735668==    by 0x4A06D8D: PDFDoc::isLinearized(bool) (poppler/PDFDoc.cc:700)
==3735668==    by 0x4A0518D: PDFDoc::getStartXRef(bool) (poppler/PDFDoc.cc:2003)
==3735668==    by 0x4A04BB8: PDFDoc::setup(std::optional<GooString> const&, std::optional<GooString> const&, std::function<void ()> const&) (poppler/PDFDoc.cc:246)
==3735668==    by 0x4A04AAB: PDFDoc::PDFDoc(std::unique_ptr<GooString, std::default_delete<GooString> >&&, std::optional<GooString> const&, std::optional<GooString> const&, void*, std::function<void ()> const&) (poppler/PDFDoc.cc:160)
==3735668==    by 0x49F93EA: LocalPDFDocBuilder::buildPDFDoc(GooString const&, std::optional<GooString> const&, std::optional<GooString> const&, void*) (poppler/LocalPDFDocBuilder.cc:0)
==3735668==    by 0x4A1FBB5: PDFDocFactory::createPDFDoc(GooString const&, std::optional<GooString> const&, std::optional<GooString> const&, void*) (poppler/PDFDocFactory.cc:62)
```

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=59840

This reverts commit 2dcbf583.

It is not used.

fixes #215

Happened as a mismerge during !1394

Resolves !1402.
Thanks, Thomas

This fixes a potential crash in setups where at least one cryptographic
signature backend is compiled in, but none is functional.

Some non-scientific experiments:
A single 8k pdf document with okular adding a simple typewriter
annotation with content "aoeu" in approximately the same place grows
without this patch to 894k. With this patch, it grows to 649k.

For comparison, if one doesn't embed the widths content at all, the same
process grew to 638k

While this isn't ground breaking gains, it is still some improvement.

https://bugzilla.redhat.com/show_bug.cgi?id=2212050

There is no BaseFont in Type 3 fonts, so we first try fontDescriptor’s
FontName, but fontDescriptor is optional so we then try the Name key.

Fixes #1396