Allow duplicated objects in incremental updates

Do not fail when encountering duplicated object in different
update section of the file.
4 jobs for fail-when-pdf-contains-duplicate-objects in 10 minutes and 22 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Build
passed #31650
build

00:10:17

passed #31651
build_clang_libcpp

00:10:10

passed #31652
build_gcc_49

00:10:06

passed #31653
build_mingw64_fedora

00:10:21