If the user configured clang with a custom GCC toolchain that will take precedence on what the ToolChainTest.cpp expects to evaluate.
This is fixed here by passing --gcc-toolchain= to the driver, in order to override any user defined GCC toolchain.
llvm-svn: 251459
This is what most people want anyways. Clang -cc1's main() will override
this but for other tools this is the most sensible default and avoids
some work.
llvm-svn: 250164