Add a couple more paths where to look for just-build Clang

[kubamracek]

Summary

Some LLDB build scripts seem to put the built Clang into different paths, let's add a couple more paths where to look for Clang. Currently used only by LLDB's ASan tests.

[zturner]

Are you using the CMake build? Even this will fail if you have multiple
clangs and you want it to choose a specific one. I would suggest setting
the LLDB_TEST_COMPILER CMake variable.

[jasonmolenda]

This patch looks fine.

[zturner]

While I agree this patch doesn't break anything, it's also not a complete fix. It would be nice to have a more complete fix, similar to what Kuba suggested with the @requiresAsan conditional.

test/lldbtest.py

           "llvm-build/Debug+Asserts/x86_64/Debug+Asserts/bin/clang",
           "llvm-build/Release/x86_64/Release/bin/clang",
           "llvm-build/Debug/x86_64/Debug/bin/clang",
+          "llvm-build/Release+Asserts/x86_64/bin/clang",
+          "llvm-build/Debug+Asserts/x86_64/bin/clang",
+          "llvm-build/Release/x86_64/bin/clang",
+          "llvm-build/Debug/x86_64/bin/clang",
         ]
         lldb_root_path = os.path.join(os.path.dirname(__file__), "..")
         for p in paths_to_try: