The test was originally skipped due to slowness. This might have been
fixed by reduced store-store zone allocations (see the linked bug).

Locally, this now runs in less than 20 seconds in full x64 debug mode.

The largest zone is < 100MB:

12089344, "V8.TFAllocateGeneralRegisters"
21954208, "graph-zone"
26181688, "../../src/compiler/verifier.cc:2000"
57895456, "instruction-zone"
98933872, "register-allocation-zone"

Drive-by: Remove tsan SLOW annotation, it's already marked SLOW in the
ALWAYS block.

Bug: v8:9572
Change-Id: Ic3ffd3de732e262f412f1d7a66448ea7228582f2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1889872
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64641}