[clang] [clang-tools-extra] [clang-query] Allow for trailing comma in matchers (PR #148018)

[Remy Farley via cfe-commits]

one-d-wide wrote:

Duh, apparently lit's internal cli interpreter, enabled due to [this](https://github.com/llvm/llvm-project/blob/02d3738be92eac38cebfb7b670673abb9538ca76/compiler-rt/test/lit.common.cfg.py#L123-L125) (setting LIT_USE_INTERNAL_SHELL=1 reproduces the error), doesn't even attempt to parse `$...` and `$(...)` substitutions.

Not sure if /dev/stdin trick would work on win32, so fixed it by first piping into [%t](https://llvm.org/docs/TestingGuide.html#substitutions).

https://github.com/llvm/llvm-project/pull/148018