Pass lsan GYP variable to swarming's test_env so that we can disable the sandbox when it's set.

This copies the logic from tools/build/scripts/slave/runtest.py in swarming.

I changed test_env.py so that it sets CHROME_DEVEL_SANDBOX to be an empty string, instead of unsetting it. The latter doesn't work as Chrome triggers checks in content/browser/browser_main_loop.cc. This is what runtest.py does.

BUG=414808,336218

Review URL: https://codereview.chromium.org/605063004

Cr-Original-Commit-Position: refs/heads/master@{#297330}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 92ee4a3cbd8284c6f63cf8ca3eed384ca70b939e

android/pylib/gtest/setup.py

@@ -118,6 +118,7 @@ def _GenerateDepsDirUsingIsolate(suite_name, isolate_file_path=None):
       '--config-variable', 'component', 'static_library',
       '--config-variable', 'fastbuild', '0',
       '--config-variable', 'icu_use_data_file_flag', '1',
+      '--config-variable', 'lsan', '0',
       # TODO(maruel): This may not be always true.
       '--config-variable', 'target_arch', 'arm',
       '--config-variable', 'use_openssl', '0',

isolate.gypi

@@ -98,6 +98,7 @@
         '--config-variable',
           'internal_gles2_conform_tests=<(internal_gles2_conform_tests)',
         '--config-variable', 'icu_use_data_file_flag=<(icu_use_data_file_flag)',
+        '--config-variable', 'lsan=<(lsan)',
         '--config-variable', 'libpeer_target_type=<(libpeer_target_type)',
         '--config-variable', 'use_openssl=<(use_openssl)',
         '--config-variable', 'target_arch=<(target_arch)',