[test] Prepare roll-out of new test runner to local runs

This adds a tri-state flag --infra-staging and --no-infra-staging, which
can be used to explicitly opt in or out of the staging test runner.

If not specified, a new architecture whitelist will enable roll-out per
arch for manual (none CI) runs.

We'll start whitelisting archs in follow ups.

Bug: v8:7343
Change-Id: I1228e48969fd379f5c231a2b8fad4afc01da94c0
Reviewed-on: https://chromium-review.googlesource.com/881169
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50812}

tools/testrunner/standard_runner.py

@@ -103,6 +103,11 @@ BUILDER_WHITELIST_STAGING = {
 }
 _RE_TYPE = type(re.compile(''))
 
+# Specifies which architectures are whitelisted to use the staging test-runner.
+# List of arch strings, e.g. "x64".
+ARCH_WHITELIST_STAGING = [
+
+]
 
 class StandardTestRunner(base_runner.BaseTestRunner):
     def __init__(self, *args, **kwargs):
@@ -152,7 +157,12 @@ class StandardTestRunner(base_runner.BaseTestRunner):
                         help="Additional flags to pass to each test command",
                         action="append", default=[])
       parser.add_option("--infra-staging", help="Use new test runner features",
-                        default=False, action="store_true")
+                        dest='infra_staging', default=None,
+                        action="store_true")
+      parser.add_option("--no-infra-staging",
+                        help="Opt out of new test runner features",
+                        dest='infra_staging', default=None,
+                        action="store_false")
       parser.add_option("--isolates", help="Whether to test isolates",
                         default=False, action="store_true")
       parser.add_option("-j", help="The number of parallel tasks to run",
@@ -225,8 +235,9 @@ class StandardTestRunner(base_runner.BaseTestRunner):
                         help="Number of runs with different random seeds")
 
     def _use_staging(self, options):
-      if options.infra_staging:
-        return True
+      if options.infra_staging is not None:
+        # True or False are used to explicitly opt in or out.
+        return options.infra_staging
       builder_configs = BUILDER_WHITELIST_STAGING.get(options.mastername, [])
       for builder_config in builder_configs:
         if (isinstance(builder_config, _RE_TYPE) and
@@ -234,6 +245,9 @@ class StandardTestRunner(base_runner.BaseTestRunner):
           return True
         if builder_config == options.buildername:
           return True
+      for arch in ARCH_WHITELIST_STAGING:
+        if self.build_config.arch == arch:
+          return True
       return False
 
     def _process_options(self, options):