[WebLayer] weblayer_browsertests should run 1 test per process

Add weblayer_browsertests to the list of BROWSER_TEST_SUITES so that the
test launcher will spawn a new java process for each browser test.

Change-Id: Idef3f66f20dc1ac8aac70fb35018f3f2650160eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1907549Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Clark DuVall <cduvall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714043}

build/android/pylib/gtest/gtest_test_instance.py

@@ -26,6 +26,7 @@ BROWSER_TEST_SUITES = [
     'android_browsertests',
     'components_browsertests',
     'content_browsertests',
+    'weblayer_browsertests',
 ]
 
 RUN_IN_SUB_THREAD_TEST_SUITES = [