[UpdateCCTestChecks] Implement --global-value-regex

`--check-globals` activates checks for all global values, and
`--global-value-regex` filters them.  For example, I'd like to use it
in OpenMP offload codegen tests to check only global variables like
`.offload_maptypes*`.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D104742