[Android WebView Layout Tests] fix run_tests_rebaseline.sh

Currently the run_tests_rebaseline.sh script does not work as
intended due to the switch to AndroidJUnitRunner. This CL fixes
the script and makes it possible to rebaseline webview layout
tests as originally intended.

Change-Id: If055a4460925ea5e18d3996d927c8596b9027a7a
Reviewed-on: https://chromium-review.googlesource.com/1150160Reviewed-by: Richard Coles <torne@chromium.org>
Commit-Queue: Tim Volodine <timvolodine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577926}

android_webview/tools/system_webview_shell/test/data/run_tests_rebaseline.sh

@@ -10,7 +10,7 @@
 #    needs to be installed on the device (e.g. system_webview_apk).
 # 2. Build system_webview_shell_layout_test_apk. This will also
 #    create a base script for running tests used here.
-# 3. Execute run_test_rebaseline.sh [builddir]
+# 3. Execute run_tests_rebaseline.sh [builddir]
 #    "builddir" is the build output directory (e.g. out/Debug/
 #    which is also the default if no directory is provided).
 #    This script will produce a shadow test_rebaseline/ directory
@@ -42,7 +42,7 @@ $RUNNER
 
 adb shell am instrument -w -e mode rebaseline -e class \
     $PACKAGE_NAME.WebViewLayoutTest \
-    $PACKAGE_NAME/$PACKAGE_NAME.WebViewLayoutTestRunner
+    $PACKAGE_NAME/android.support.test.runner.AndroidJUnitRunner
 adb pull $DEVICE_WEBVIEW_TEST_PATH ../test_rebaseline/
 
 exit 0