Extend `#pragma clang __debug dump` to support not only single identifier, but an expression as well. This makes it possible to test ADL and overload resolution directly, without being creative to make them observable via diagnostics (e.g. when [[ http://eel.is/c++draft/over.match.best | over.match.best ]] is involved). This implementation has a known limitation of not supporting dependent expressions properly, but it's quite useful even without such support.
Differential Revision: https://reviews.llvm.org/D144115
This moves everything primarily testing the functionality of -ast-dump and -ast-print into their own directory, rather than leaving the tests spread around the testing directory.
llvm-svn: 348017
