siso: enable Clang crash report capture in remote execution

Updates Siso configuration to parse -fcrash-diagnostics-dir flags from Clang commands. If found, the specified directory is registered as an auxiliary output via ctx.actions.fix(auxiliary_log_output_dirs=...).

This ensures that crash reports (source, shell script, cache) generated during remote compile failures are captured and uploaded by Siso, making them available for debugging.

Bug: 479224195
Change-Id: Icfb0a1162139030ad4aead58eb2fb6cc2d85b525
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7561710
Reviewed-by: Fumitoshi Ukai <ukai@google.com>
Commit-Queue: Yuke Liao <liaoyuke@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>
Cr-Commit-Position: refs/heads/main@{#1584533}