Enable TF for testing benchmarks.

test/benchmarks/testcfg.py

Index: test/benchmarks/testcfg.py
diff --git a/test/benchmarks/testcfg.py b/test/benchmarks/testcfg.py
index c94a35ffd9f17112a7611f141dc2463febecc5d0..8c573ba30b11cc53c4f03e2d74fd65e79fbd01ae 100644
--- a/test/benchmarks/testcfg.py
+++ b/test/benchmarks/testcfg.py
@@ -31,6 +31,7 @@ import shutil
 import subprocess
 import tarfile
 
+from testrunner.local import statusfile
 from testrunner.local import testsuite
 from testrunner.objects import testcase
 
@@ -183,8 +184,12 @@ class BenchmarksTestSuite(testsuite.TestSuite):
     os.chdir(old_cwd)
 
   def VariantFlags(self, testcase, default_flags):
-    # Both --nocrankshaft and --stressopt are very slow.
-    return [[]]
+    if testcase.outcomes and statusfile.OnlyStandardVariant(testcase.outcomes):
+      return [[]]
+    # Both --nocrankshaft and --stressopt are very slow. Add TF but without
+    # always opt to match the way the benchmarks are run for performance
+    # testing.
+    return [[], ["--turbo-filter=*"]]
 
 
 def GetSuite(name, root):