[compiler-rt] [compiler-rt][rtsan] Introduce first end to end RTsan lit tests, enable instrumented unit tests (PR #105732)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu` running on `sie-linux-worker3` while building `compiler-rt` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/3947

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'RealtimeSanitizer-Unit :: ./Rtsan-x86_64-Test/15/35' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/runtimes/runtimes-bins/compiler-rt/lib/rtsan/tests/./Rtsan-x86_64-Test-RealtimeSanitizer-Unit-2029597-15-35.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=35 GTEST_SHARD_INDEX=15 /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/runtimes/runtimes-bins/compiler-rt/lib/rtsan/tests/./Rtsan-x86_64-Test
--

Script:
--
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/runtimes/runtimes-bins/compiler-rt/lib/rtsan/tests/./Rtsan-x86_64-Test --gtest_filter=RtsanFileTest.OpenCreatesFileWithProperMode
--
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp:198: Failure
Value of: st.st_mode & 0777
Expected: is equal to 420
  Actual: 384


/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp:198
Value of: st.st_mode & 0777
Expected: is equal to 420
  Actual: 384



********************


```

</details>

https://github.com/llvm/llvm-project/pull/105732