v8 benchmarks: Allow any metric below 'v8-gc-mark-compactor-'

These metrics are high level and do not include subscopes.

Examples:
- v8-gc-mark-compactor-total
- v8-gc-mark-compactor-mmu
- v8-gc-mark-compactor-marking-total

No-try: true
Tbr: nednguyen@chromium.org
Change-Id: I6feafb6971f0904d1d9bd31201d1be2e63258049
Reviewed-on: https://chromium-review.googlesource.com/c/1304479Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603479}

tools/perf/benchmarks/v8_browsing.py

@@ -25,8 +25,7 @@ _V8_GC_HIGH_LEVEL_STATS_RE = re.compile(r'^v8-gc-('
     r'incremental-finalize_|'
     r'incremental-step_|'
     r'latency-mark-compactor_|'
-    r'mark-compactor_|'
-    r'mark-compactor-mmu_|'
+    r'mark-compactor-|'
     r'memory-mark-compactor_|'
     r'scavenger_|'
     r'total_)')