[test-runner] Make perf runner robust for missing executable.

tools/run_perf.py

 #!/usr/bin/env python
 # Copyright 2014 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Performance runner for d8.
 
 Call e.g. with tools/run-perf.py --arch ia32 some_suite.json
 
@@ skipping 468 matching lines @@
     pass
 
   def PostExecution(self):
     pass
 
   def PreTests(self, node, path):
     if isinstance(node, Runnable):
       node.ChangeCWD(path)
 
   def Run(self, runnable, count):
-    output = commands.Execute(runnable.GetCommand(self.shell_dir),
-                              timeout=runnable.timeout)
+    try:
+      output = commands.Execute(runnable.GetCommand(self.shell_dir),
+                                timeout=runnable.timeout)
+    except OSError as e:
+      print ">>> OSError (#%d):" % (count + 1)
+      print e
+      return ""
     print ">>> Stdout (#%d):" % (count + 1)
     print output.stdout
     if output.stderr:  # pragma: no cover
       # Print stderr for debugging.
       print ">>> Stderr (#%d):" % (count + 1)
       print output.stderr
     if output.timed_out:
       print ">>> Test timed out after %ss." % runnable.timeout
     return output.stdout
 
@@ skipping 210 matching lines @@
 
   if options.json_test_results:
     results.WriteToFile(options.json_test_results)
   else:  # pragma: no cover
     print results
 
   return min(1, len(results.errors))
 
 if __name__ == "__main__":  # pragma: no cover
   sys.exit(Main(sys.argv[1:]))