[clang] [cmake] Refactor clang unittest cmake (PR #133545)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `lldb-aarch64-windows` running on `linaro-armv8-windows-msvc-05` while building `clang` at step 6 "test".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/141/builds/7528

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

```
Step 6 (test) failure: build (failure)
...
PASS: lldb-api :: functionalities/wrong_commands/TestWrongCommands.py (699 of 2104)
UNSUPPORTED: lldb-api :: iohandler/autosuggestion/TestAutosuggestion.py (700 of 2104)
UNSUPPORTED: lldb-api :: iohandler/completion/TestIOHandlerCompletion.py (701 of 2104)
UNSUPPORTED: lldb-api :: iohandler/resize/TestIOHandlerResize.py (702 of 2104)
UNSUPPORTED: lldb-api :: iohandler/resize/TestIOHandlerResizeNoEditline.py (703 of 2104)
UNSUPPORTED: lldb-api :: iohandler/sigint/TestIOHandlerPythonREPLSigint.py (704 of 2104)
UNSUPPORTED: lldb-api :: iohandler/sigint/TestProcessIOHandlerInterrupt.py (705 of 2104)
UNSUPPORTED: lldb-api :: iohandler/stdio/TestIOHandlerProcessSTDIO.py (706 of 2104)
UNSUPPORTED: lldb-api :: iohandler/unicode/TestUnicode.py (707 of 2104)
TIMEOUT: lldb-api :: functionalities/conditional_break/TestConditionalBreak.py (708 of 2104)
******************** TEST 'lldb-api :: functionalities/conditional_break/TestConditionalBreak.py' FAILED ********************
Script:
--
C:/Users/tcwg/scoop/apps/python/current/python.exe C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/llvm-project/lldb\test\API\dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./lib --env LLVM_INCLUDE_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/include --env LLVM_TOOLS_DIR=C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin --arch aarch64 --build-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex --lldb-module-cache-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex/module-cache-lldb\lldb-api --clang-module-cache-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/lldb-test-build.noindex/module-cache-clang\lldb-api --executable C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/lldb.exe --compiler C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/clang.exe --dsymutil C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin/dsymutil.exe --make C:/Users/tcwg/scoop/shims/make.exe --llvm-tools-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./bin --lldb-obj-root C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/tools/lldb --lldb-libs-dir C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/build/./lib --skip-category=watchpoint C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\API\functionalities\conditional_break -p TestConditionalBreak.py
--
Exit Code: 15
Timeout: Reached timeout of 600 seconds

Command Output (stdout):
--
lldb version 21.0.0git (https://github.com/llvm/llvm-project.git revision 5ffd9bdb50b5753bbf668e4eab3647dfb46cd0d6)
  clang revision 5ffd9bdb50b5753bbf668e4eab3647dfb46cd0d6
  llvm revision 5ffd9bdb50b5753bbf668e4eab3647dfb46cd0d6
Executing commands in 'C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\llvm-project\lldb\test\API\functionalities\conditional_break\.lldb'.
(lldb) breakpoint set -n c
Breakpoint 1: where = a.out`c + 8 at main.c:31:12, address = 0x0000000140001094
(lldb) command script import -r conditional_break.py
(lldb) breakpoint command add 1 -F "conditional_break.stop_if_called_from_a"

--
Command Output (stderr):
--
UNSUPPORTED: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_with_command_dsym (TestConditionalBreak.ConditionalBreakTestCase.test_with_command_dsym) (test case does not fall in any category of interest for this run) 

PASS: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_with_command_dwarf (TestConditionalBreak.ConditionalBreakTestCase.test_with_command_dwarf)

UNSUPPORTED: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_with_command_dwo (TestConditionalBreak.ConditionalBreakTestCase.test_with_command_dwo) (test case does not fall in any category of interest for this run) 

UNSUPPORTED: LLDB (C:\Users\tcwg\llvm-worker\lldb-aarch64-windows\build\bin\clang.exe-aarch64) :: test_with_python_dsym (TestConditionalBreak.ConditionalBreakTestCase.test_with_python_dsym) (test case does not fall in any category of interest for this run) 


--

********************
PASS: lldb-api :: lang/c/anonymous/TestAnonymous.py (709 of 2104)
UNSUPPORTED: lldb-api :: lang/c/bitfields/TestBitfields.py (710 of 2104)
UNSUPPORTED: lldb-api :: lang/c/blocks/TestBlocks.py (711 of 2104)
PASS: lldb-api :: lang/c/builtin-types/TestCBuiltinTypes.py (712 of 2104)
PASS: lldb-api :: lang/c/array_types/TestArrayTypes.py (713 of 2104)

```

</details>

https://github.com/llvm/llvm-project/pull/133545