Remove abort from FcCompareSize.

There doesn't appear to be a good reason to abort when 'v1' has type
FcTypeRange. If there does turn out to be a good reason for this then it
should be better documented and the code for handling this case removed.
At worst it seems -1 should be returned as it is for other unknown
types. It is possible this is left over debug code from the initial
implementation.
10 jobs for remove_abort in 12 minutes and 57 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Build
passed #6005055
gst-macos-10.15
meson macos

00:04:22

passed #6005052
meson-mingw-w64-build

00:04:49

manual #6005056
docker windows 1809 allowed to fail manual
meson msys2
passed #6005050
meson-shared-build

00:05:30

passed #6005051
meson-static-build

00:05:01

passed #6005053
docker windows 1809
meson vs2017 amd64

00:01:46

passed #6005054
docker windows 1809
meson vs2017 x86

00:01:46

passed #6005049
mingw-build

00:05:27

passed #6005047
shared-build

00:08:34

passed #6005048
static-build

00:05:55