This patch simplifies comparison of results that have filesystem
paths. E.g., (assuming different values of <N>):
<cut>
Running /home/user/gcc-N/gcc/testsuite/gcc.target/aarch64/sve/acle/aarch64-sve-acle-asm.exp ...
ERROR: tcl error sourcing /home/user/gcc-N/gcc/testsuite/gcc.target/aarch64/sve/acle/aarch64-sve-acle-asm.exp.
</cut>
We add "--srcpath <regex>", option, and set it by default to
"[^ ]+/testsuite/", which works well for all components of the GNU
Toolchain. We then remove substrings matching <regex> from paths of
.exp files and from occasional "ERROR:" results.
contrib/ChangeLog:
* testsuite-management/validate_failures.py (TestResult,)
(ParseManifestWorker, ParseSummary, Main): Handle new option
"--srcpath <regex>".