[clang] [clang][test] Rebuild lld if the clang driver tests will use it (PR #174512)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ppc64le-lld-multistage-test` running on `ppc64le-lld-multistage-test` while building `clang` at step 12 "build-stage2-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/168/builds/18013

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

```
Step 12 (build-stage2-unified-tree) failure: build (failure) (timed out)
...
1275.433 [133/12/6688] Building CXX object tools/clang/unittests/CMakeFiles/AllClangUnitTests.dir/Tooling/RecursiveASTVisitorTests/CallbacksBinaryOperator.cpp.o
1276.658 [133/11/6689] Building CXX object tools/clang/unittests/CMakeFiles/AllClangUnitTests.dir/ASTMatchers/ASTMatchersNodeTest.cpp.o
1325.977 [133/10/6690] Building CXX object tools/clang/unittests/CMakeFiles/AllClangUnitTests.dir/ASTMatchers/ASTMatchersNarrowingTest.cpp.o
1333.214 [133/9/6691] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/AMDGPUTargetMachine.cpp.o
1361.796 [133/8/6692] Building CXX object lib/Target/AMDGPU/CMakeFiles/LLVMAMDGPUCodeGen.dir/AMDGPUInstructionSelector.cpp.o
1402.235 [133/7/6693] Building CXX object tools/clang/lib/StaticAnalyzer/Checkers/CMakeFiles/obj.clangStaticAnalyzerCheckers.dir/StdLibraryFunctionsChecker.cpp.o
1423.017 [133/6/6694] Building CXX object lib/Target/AMDGPU/AsmParser/CMakeFiles/LLVMAMDGPUAsmParser.dir/AMDGPUAsmParser.cpp.o
1431.316 [133/5/6695] Building CXX object tools/clang/lib/ASTMatchers/Dynamic/CMakeFiles/obj.clangDynamicASTMatchers.dir/Registry.cpp.o
1460.656 [133/4/6696] Building CXX object tools/clang/unittests/CMakeFiles/AllClangUnitTests.dir/AST/ASTImporterTest.cpp.o
1703.461 [133/3/6697] Building CXX object tools/clang/unittests/CMakeFiles/AllClangUnitTests.dir/ASTMatchers/ASTMatchersTraversalTest.cpp.o
command timed out: 1200 seconds without output running [b'ninja'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=2904.558556

```

</details>

https://github.com/llvm/llvm-project/pull/174512