Move fontconfig parts of test_fonts into a subdirectory

PDFium loads fonts directly, so only requires the test_fonts files
without the fontconfig parts.  This CL moves the fontconfig-
specific parts of test_fonts into a subdirectory so that the
fontconfig dependency may be removed.  This is required since otherwise
building 'all' would fail due to a missing fontconfig dependency.

R=thestig

Bug: 1250250
Change-Id: I773ed63a236e09666e1850cd3cb82765b395ae9f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3227476
Auto-Submit: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#933047}
NOKEYCHECK=True
GitOrigin-RevId: 7eeb3469934941da58b774a7fea5e61f610c5a80
6 files changed