Disable BenchmarkSmokeTest.v8.runtime_stats.top_25 on Mac.

Test consistently failing on Mac10.11 and flaky on Mac10.10.

TBR=nednguyen@chromium.org

No-Try: true
No-Presubmit: true
No-Tree-Checks: true

Bug: 829161
Change-Id: I89fc7186a5c3c76853ec666bca57409e76950d73
Reviewed-on: https://chromium-review.googlesource.com/999232
Commit-Queue: Darren Shen <shend@chromium.org>
Reviewed-by: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548710}

tools/perf/expectations.config

@@ -409,6 +409,7 @@ crbug.com/812618 [ Android_Webview ] v8.detached_context_age_in_gc/Docs_(1_open_
 crbug.com/664318 [ Android ] v8.runtime_stats.top_25/* [ Skip ]
 crbug.com/664318 [ Win ] v8.runtime_stats.top_25/* [ Skip ]
 crbug.com/829504 [ Linux ] v8.runtime_stats.top_25/https://www.google.de/search?q=v8 [ Skip ]
+crbug.com/829161 [ Mac ] v8.runtime_stats.top_25/https://www.google.de/search?q=v8 [ Skip ]
 
 # Benchmark: wasm
 [ Android_One ] wasm/WasmSpaceBuggy [ Skip ]