[roll] Roll fuchsia [starnix/tests] Excercise invalidating mounted FUSE dir

When a FUSE entry is found to be invalid after revalidation, any mounts
at that entry should be unmounted.

The newly introduced tests pass when run on Linux with `CAP_SYS_ADMIN`:
```
ghanan@ghanan-cloudtop:~/Projects/fuchsia$ TZ=America/Los_Angeles date
Wed May 15 11:03:38 AM PDT 2024
ghanan@ghanan-cloudtop:~/Projects/fuchsia$ git log -1 --format="%H (%ch) %s"
b86e8e150baf9475d181de10cbdbb7b93617da8c (8 minutes ago) [starnix/tests] Excercise invalidating mounted FUSE dir
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="*InvalidateMountDir*"
Welcome to fx test 🧪

Found 653 total tests in //out/core.qemu-x64/tests.json

Plan to run 1 test

Refreshing 2 targets
> fx build --toolchain=//build/toolchain:host_x64 //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'
ninja: no work to do.
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=*InvalidateMountDir*
Note: Google Test filter = *InvalidateMountDir*
Note: Randomizing tests' orders with a seed of 10694 .
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from FuseServerTest
[ RUN      ] FuseServerTest.InvalidateMountDir
[       OK ] FuseServerTest.InvalidateMountDir (147 ms)
[----------] 1 test from FuseServerTest (147 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (148 ms total)
[  PASSED  ] 1 test.
PASSED: linux_x64/syscalls_cpp_test_bin

RAN: 1 PASSED: 1 FAILED: 0 SKIPPED: 0

Completed in 4.927s

ghanan@ghanan-cloudtop:~/Projects/fuchsia$ TZ=America/Los_Angeles date
Wed May 15 11:04:04 AM PDT 2024
```

Original-Fixed: b/339867956
Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1045043
Original-Revision: 48060b4e0c4a5a5a8805d8f582ebbad27f90d7e6
GitOrigin-RevId: a3ad879fb3a2ff8800d6289eaddf0fa4d9c53d36
Change-Id: I5ad6e3ee30b967ed253352526c0c2897799648b1