[clang] Reland [clang][modules-driver] Add scanner to detect C++20 module presence (PR #147630)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-arm64-windows-msvc` running on `linaro-armv8-windows-msvc-01` while building `clang` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/207/builds/4313

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
1048.609 [144/10/1037] Linking CXX static library lib\clangToolingSyntax.lib
1048.685 [143/10/1038] Linking CXX static library lib\clangDependencyScanning.lib
1048.740 [142/10/1039] Building CXX object tools/clang/tools/libclang/CMakeFiles/libclang.dir/Indexing.cpp.obj
1049.833 [141/10/1040] Building CXX object tools/clang/lib/ASTMatchers/Dynamic/CMakeFiles/obj.clangDynamicASTMatchers.dir/VariantValue.cpp.obj
1051.189 [140/10/1041] Building CXX object tools/flang/lib/Frontend/CMakeFiles/flangFrontend.dir/ParserActions.cpp.obj
1051.439 [139/10/1042] Linking CXX static library lib\flangFrontend.lib
1051.626 [138/10/1043] Linking CXX static library lib\flangFrontendTool.lib
1052.187 [137/10/1044] Building CXX object tools/clang/lib/Tooling/Inclusions/Stdlib/CMakeFiles/obj.clangToolingInclusionsStdlib.dir/StandardLibrary.cpp.obj
1053.161 [136/10/1045] Building CXX object tools/clang/lib/Analysis/FlowSensitive/Models/CMakeFiles/obj.clangAnalysisFlowSensitiveModels.dir/ChromiumCheckModel.cpp.obj
1053.702 [135/10/1046] Linking CXX executable bin\flang.exe
FAILED: bin/flang.exe 
C:\WINDOWS\system32\cmd.exe /C "cd . && C:\Users\tcwg\scoop\apps\cmake\3.29.2\bin\cmake.exe -E vs_link_exe --intdir=tools\flang\tools\flang-driver\CMakeFiles\flang.dir --rc=C:\PROGRA~2\WI3CF2~1\10\bin\100226~1.0\arm64\rc.exe --mt=C:\PROGRA~2\WI3CF2~1\10\bin\100226~1.0\arm64\mt.exe --manifests  -- C:\Users\tcwg\scoop\apps\llvm-arm64\current\bin\lld-link.exe /nologo @CMakeFiles\flang.rsp  /out:bin\flang.exe /implib:lib\flang.lib /pdb:bin\flang.pdb /version:0.0 /machine:ARM64 /STACK:10000000 /INCREMENTAL:NO /subsystem:console && C:\WINDOWS\system32\cmd.exe /C "cd /D C:\Users\tcwg\llvm-worker\flang-arm64-windows-msvc\build\tools\flang\tools\flang-driver && C:\Users\tcwg\scoop\apps\cmake\3.29.2\bin\cmake.exe -E copy C:/Users/tcwg/llvm-worker/flang-arm64-windows-msvc/build/bin/flang.exe C:/Users/tcwg/llvm-worker/flang-arm64-windows-msvc/build/./bin/flang-new.exe""
LINK: command "C:\Users\tcwg\scoop\apps\llvm-arm64\current\bin\lld-link.exe /nologo @CMakeFiles\flang.rsp /out:bin\flang.exe /implib:lib\flang.lib /pdb:bin\flang.pdb /version:0.0 /machine:ARM64 /STACK:10000000 /INCREMENTAL:NO /subsystem:console /MANIFEST:EMBED,ID=1" failed (exit code 1) with the following output:
lld-link: error: undefined symbol: bool __cdecl clang::scanInputForCXX20ModulesUsage(class llvm::StringRef)
>>> referenced by clangDriver.lib(Driver.cpp.obj):(private: class llvm::ErrorOr<bool> __cdecl clang::driver::Driver::ScanInputsForCXX20ModulesUsage(class llvm::SmallVector<struct std::pair<enum clang::driver::types::ID, class llvm::opt::Arg const *>, 16> const &) const)

1055.118 [135/9/1047] Building CXX object tools/clang/tools/libclang/CMakeFiles/libclang.dir/CXExtractAPI.cpp.obj
1057.551 [135/8/1048] Building CXX object tools/clang/lib/Tooling/Transformer/CMakeFiles/obj.clangTransformer.dir/SourceCode.cpp.obj
1059.278 [135/7/1049] Building CXX object tools/clang/lib/Tooling/Transformer/CMakeFiles/obj.clangTransformer.dir/Parsing.cpp.obj
1059.443 [135/6/1050] Building CXX object tools/clang/lib/Tooling/Transformer/CMakeFiles/obj.clangTransformer.dir/RangeSelector.cpp.obj
1060.988 [135/5/1051] Building CXX object tools/clang/lib/Tooling/Transformer/CMakeFiles/obj.clangTransformer.dir/RewriteRule.cpp.obj
1061.388 [135/4/1052] Building CXX object tools/clang/lib/Analysis/FlowSensitive/Models/CMakeFiles/obj.clangAnalysisFlowSensitiveModels.dir/UncheckedOptionalAccessModel.cpp.obj
1062.884 [135/3/1053] Building CXX object tools/clang/lib/Tooling/Transformer/CMakeFiles/obj.clangTransformer.dir/SourceCodeBuilders.cpp.obj
1063.835 [135/2/1054] Building CXX object tools/clang/lib/Tooling/Transformer/CMakeFiles/obj.clangTransformer.dir/Stencil.cpp.obj
1094.247 [135/1/1055] Building CXX object tools/clang/lib/ASTMatchers/Dynamic/CMakeFiles/obj.clangDynamicASTMatchers.dir/Registry.cpp.obj
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/147630