[test] Stress concurrent inlining on numfuzz

This will give extra coverage of the mode on the numfuzz tsan bot.

No-Try: true
Bug: chromium:11655
Change-Id: Ifcc4ad304116fa1b0331cc48e41c07405193d514
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2862809
Auto-Submit: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74316}

tools/testrunner/testproc/fuzzer.py

@@ -43,6 +43,7 @@ EXTRA_FLAGS = [
   (0.1, '--regexp-tier-up-ticks=10'),
   (0.1, '--regexp-tier-up-ticks=100'),
   (0.1, '--stress-background-compile'),
+  (0.1, '--stress-concurrent-inlining'),
   (0.1, '--stress-lazy-source-positions'),
   (0.1, '--stress-wasm-code-gc'),
   (0.1, '--turbo-instruction-scheduling'),