Revert "Roll src/third_party/fontconfig/src/ 8cf0ce700..685f2ec4a (24 commits)"

This reverts commit eaa8763e33669a76316cb82d703ea72845d73639.

Reason for revert:
LUCI Bisection has identified this change as the cause of a test failure. See the analysis: https://ci.chromium.org/ui/p/chromium/bisection/test-analysis/b/5755983423864832

Sample build with failed test: https://ci.chromium.org/b/8713059050676341729
Affected test(s):
[ninja://:chrome_wpt_tests/external/wpt/FileAPI/BlobURL/cross-partition-navigation.https.html](https://ci.chromium.org/ui/test/chromium/ninja:%2F%2F:chrome_wpt_tests%2Fexternal%2Fwpt%2FFileAPI%2FBlobURL%2Fcross-partition-navigation.https.html?q=VHash%3A8864e7c73d664576)

If this is a false positive, please report it at http://b.corp.google.com/createIssue?component=1199205&description=Analysis%3A+https%3A%2F%2Fci.chromium.org%2Fui%2Fp%2Fchromium%2Fbisection%2Ftest-analysis%2Fb%2F5755983423864832&format=PLAIN&priority=P3&title=Wrongly+blamed+https%3A%2F%2Fchromium-review.googlesource.com%2Fc%2Fchromium%2Fsrc%2F%2B%2F6618346&type=BUG

Original change's description:
> Roll src/third_party/fontconfig/src/ 8cf0ce700..685f2ec4a (24 commits)
>
> https://chromium.googlesource.com/external/fontconfig.git/+log/8cf0ce700a8a..685f2ec4a7e3
>
> $ git log 8cf0ce700..685f2ec4a --date=short --no-merges --format='%ad %ae %s'
> 2025-05-30 akira Do not hardcode a cache version
> 2025-05-30 akira doc: rewrite check-missing-doc in Python
> 2025-05-30 akira Add bitmap-conf build option to choose default bitmap conf
> 2025-05-30 thomasanderson Fix heap buffer underflow in FcConfigXdgDataDirs
> 2025-05-28 akira Avoid possibly invalid access on MT
> 2025-05-28 akira Fix a memory leak in default_langs
> 2025-05-28 akira Call FcMutexUnlock only when valid instance is available
> 2025-05-28 akira Revert "test-crbug1004254: hold FcConfig during running a test in a thread"
> 2025-05-28 akira Simplify FcConfigFini()
> 2025-05-26 akira test-crbug1004254: hold FcConfig during running a test in a thread
> 2025-05-26 akira test: add a test scenario for 48-guessfamily.conf
> 2025-05-26 akira test: add a pattern test
> 2025-05-26 akira conf.d: Add a conf to guess a generic-family for substitution
> 2025-05-22 akira Increase a reference count for default FcConfig instance with FcInit()
> 2025-05-22 akira Free the mutex object only when there are no references to the default FcConfig instance
> 2025-05-22 akira Free the mutex object only when all cache objects isn't referenced
> 2025-05-16 akira Drop FcObjectFini() from FcFini() to fix memory leaks
> 2025-05-16 akira Drop the configuration path migration code
> 2025-05-08 akira test: do not free FcFontSet From FcConfigGetFonts
> 2025-05-07 akira Drop FcDefaultFini() from FcFini() to fix memory leaks
> 2025-05-16 drott [Fontations] Add woff wrapper and filename if file is woff or woff2
> 2025-05-14 drott [Fontations] Add fontwrapper, filename and symbol elements to pattern
> 2025-05-14 drott [Fontations] Add langset pattern element
> 2025-05-14 drott [Fontations] Add charset pattern element
>
> Created with:
>   roll-dep src/third_party/fontconfig/src
>
> R=drott
>
> Fixed: 342569142
> Change-Id: I878acd2a15f0c61d1a1f7196450e219820558cb2
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6618346
> Auto-Submit: Thomas Anderson <thomasanderson@chromium.org>
> Reviewed-by: Dominik Röttsches <drott@chromium.org>
> Commit-Queue: Dominik Röttsches <drott@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1468845}
>

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I3e0f681c6152f2f04f3a1caa3cdd9ae03a8de56b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6618923
Reviewed-by: Jonathan Lee <jonathanjlee@google.com>
Commit-Queue: Jonathan Lee <jonathanjlee@google.com>
Owners-Override: Khalid Peer <khalidpeer@chromium.org>
Reviewed-by: Khalid Peer <khalidpeer@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1469066}