Revert Android isolated test perf output argument.

The original argument is needed by WebRTC.

Bug: angleproject:3162
Bug: 931731
Change-Id: I98c8dbb054ce5cd3c989c8fdd55195e4cf4a7c69
Cq-Do-Not-Cancel-Tryjobs: true
Tbr: dpranke@google.com
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412371Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Mirko Bonadei <mbonadei@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807460}

build/android/pylib/local/device/local_device_gtest_run.py

@@ -651,7 +651,7 @@ class LocalDeviceGtestRun(local_device_test_run.LocalDeviceTestRun):
                          device_tmp_results_file.name)
 
           if test_perf_output_filename:
-            flags.append('--isolated-script-test-perf-output=%s' %
+            flags.append('--isolated_script_test_perf_output=%s' %
                          isolated_script_test_perf_output.name)
 
           logging.info('flags:')