[test] Add android perf trybots.

BUG=chromium:502176
LOG=n
NOTRY=true

Review URL: https://codereview.chromium.org/1217503008

Cr-Commit-Position: refs/heads/master@{#29491}

tools/try_perf.py

@@ -16,6 +16,10 @@ BOTS = {
   '--linux32': 'v8_linux32_perf_try',
   '--linux64': 'v8_linux64_perf_try',
   '--linux64_haswell': 'v8_linux64_haswell_perf_try',
+  '--nexus5': 'v8_nexus5_perf_try',
+  '--nexus7': 'v8_nexus7_perf_try',
+  '--nexus9': 'v8_nexus9_perf_try',
+  '--nexus10': 'v8_nexus10_perf_try',
 }
 
 DEFAULT_BOTS = [