[clang] [llvm] [SystemZ][z/OS] Add new openFileForReadBinary function, and pass IsText parameter to getBufferForFile (PR #111723)

[Abhina Sree via cfe-commits]

abhina-sree wrote:

@cor3ntin, I've added support for #embed handling now, I've added a z/OS only testcase clang/test/Preprocessor/embed_zos.c which is a copy of clang/test/Preprocessor/embed_art.c except it changes the file tag to be non-ascii which is now working with the latest commit.

https://github.com/llvm/llvm-project/pull/111723