[roll] Roll fuchsia [starnix/tests] Exercise revalidating cached entry

The newly introduced tests pass when run on Linux with `CAP_SYS_ADMIN`:
```
ghanan@ghanan-cloudtop:~/Projects/fuchsia$ TZ=America/Los_Angeles date
Thu May  2 09:39:59 AM PDT 2024
ghanan@ghanan-cloudtop:~/Projects/fuchsia$ git log -1 --format="%H (%ch) %s"
df1970cb09d32696e725c48eb4b6abad65bfb822 (33 seconds ago) [starnix/tests] Exercise revalidating cached entry
ghanan@ghanan-cloudtop:~/Projects/fuchsia$ capsh --current
Current: cap_net_admin,cap_net_raw,cap_sys_chroot,cap_sys_admin=eip
Current IAB: ^cap_net_admin,^cap_net_raw,^cap_sys_chroot,^cap_sys_admin
ghanan@ghanan-cloudtop:~/Projects/fuchsia$ fx test --host -o syscalls_cpp_host_test -- --gtest_filter="*PathWalkRefreshDirEntry*"

You are using the new fx test, which is currently ready for general use ✅
See details here: https://fuchsia.googlesource.com/fuchsia/+/refs/heads/main/scripts/fxtest/rewrite
To go back to the old fx test, use `fx --enable=legacy_fxtest test`, and please file a bug under b/293917801.

Logging all output to: /usr/local/google/home/ghanan/Projects/fuchsia/out/core.qemu-x64/fxtest-2024-05-02T16:40:08.339008.log.json.gz
Use the `--logpath` argument to specify a log location or `--no-log` to disable

Found 639 total tests in //out/core.qemu-x64/tests.json

Plan to run 1 test

Refreshing 2 targets
> fx build --host //src/starnix/tests/syscalls/cpp:syscalls_cpp_host_tests
Use --no-build to skip building

Executing build. Status output suspended.
Building Ninja target(s): host_x64/obj/src/starnix/tests/syscalls/cpp/syscalls_cpp_host_tests.stamp
ninja: Entering directory `/usr/local/google/home/ghanan/Projects/fuchsia/out/core.qemu-x64'
[4/4](0) STAMP host_x64/obj/src/starnix/tests/syscalls/cpp/syscalls_cpp_host_tests.stamp

Running 1 tests

Starting: linux_x64/syscalls_cpp_test_bin (NOT HERMETIC)
Command: /usr/local/google/home/ghanan/Projects/fuchsia/out/core.qemu-x64/linux_x64/syscalls_cpp_test_bin --gtest_filter=*PathWalkRefreshDirEntry*
Note: Google Test filter = *PathWalkRefreshDirEntry*
Note: Randomizing tests' orders with a seed of 85409 .
[==========] Running 4 tests from 1 test suite.
[----------] Global test environment set-up.
[----------] 4 tests from FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest
[ RUN      ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/0
[       OK ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/0 (214 ms)
[ RUN      ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/2
[       OK ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/2 (226 ms)
[ RUN      ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/3
[       OK ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/3 (220 ms)
[ RUN      ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/1
[       OK ] FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest.PathWalkRefreshDirEntry/1 (223 ms)
[----------] 4 tests from FusePathWalkRefreshDirEntryTest/FusePathWalkRefreshDirEntryTest (885 ms total)

[----------] Global test environment tear-down
[==========] 4 tests from 1 test suite ran. (885 ms total)
[  PASSED  ] 4 tests.

PASSED: linux_x64/syscalls_cpp_test_bin
Results: PASS: 1 FAIL: 0 SKIP: 0

Completed in 19.311s [16/16 complete]
Output was logged to: out/core.qemu-x64/fxtest-2024-05-02T16:40:08.339008.log.json.gz

ghanan@ghanan-cloudtop:~/Projects/fuchsia$ TZ=America/Los_Angeles date
Thu May  2 09:40:31 AM PDT 2024
```

Original-Bug: b/324955805, b/331965426, b/331965660
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1037034
Original-Revision: 643639245969ebfd58179f356d657bde7d8e5f51
GitOrigin-RevId: d56b089142bc19811fda8ecc09d9b9d92a312cbe
Change-Id: Ie1741bd3e7aba918a36b0779f0a6918ab3721e66
diff --git a/stem b/stem
index 382990f..021f4d7 100644
--- a/stem
+++ b/stem
@@ -11,7 +11,7 @@
              githooks="integration/git-hooks"
              remote="https://fuchsia.googlesource.com/fuchsia"
              gerrithost="https://fuchsia-review.googlesource.com"
-             revision="2c587c2f690c6903c5efe75191eb9fb09094f481"/>
+             revision="643639245969ebfd58179f356d657bde7d8e5f51"/>
   </projects>
   <hooks>
     <hook name="install-environment"