Revert of Reset PYTHONPATH in runtest_wrapper.py (patchset #5 id:80001 of https://codereview.chromium.org/1224593002/)

Reason for revert:
Failed telemetry_unittests on Mac10.8 Tests (http://build.chromium.org/p/chromium.mac/builders/Mac10.8%20Tests/builds/4576):

[1/1] telemetry.telemetry_dependencies_unittest.TelemetryDependenciesTest.testNoNewTelemetryDependencies failed unexpectedly 10.7608s:
  Traceback (most recent call last):
    File "/Volumes/data/b/build/slave/Mac10_8_Tests/build/src/tools/telemetry/telemetry/telemetry_dependencies_unittest.py", line 57, in testNoNewTelemetryDependencies
      'Extra dependencies:\n%s' % '\n'.join(extra_dep_paths))
  AssertionError: Your patch adds new dependencies to telemetry. Please contact aiolos@,dtu@, or nednguyen@ on how to proceed with this change. Extra dependencies:
  /Volumes/data/b/build/slave/Mac10_8_Tests/build/src/third_party/ply/README.chromium
  /Volumes/data/b/build/slave/Mac10_8_Tests/build/src/third_party/ply/license.patch
  /Volumes/data/b/build/slave/Mac10_8_Tests/build/src/third_party/ply/__init__.py
  /Volumes/data/b/build/slave/Mac10_8_Tests/build/src/third_party/ply/LICENSE
  /Volumes/data/b/build/slave/Mac10_8_Tests/build/src/third_party/ply/lex.py
  /Volumes/data/b/build/slave/Mac10_8_Tests/build/src/third_party/ply/README
  /Volumes/data/b/build/slave/Mac10_8_Tests/build/src/third_party/ply/yacc.py

Original issue's description:
> Reset PYTHONPATH in runtest_wrapper.py
>
> This ensures we won't use build-side python modules,
> and that any changes in src-side modules do take effect.
>
> BUG=506498
>
> Committed: https://crrev.com/2bafb027d8916c84ea4e70f933b9df7eed4a8a87
> Cr-Commit-Position: refs/heads/master@{#337372}

TBR=akuegel@chromium.org,sergiyb@chromium.org,phajdan.jr@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=506498

Review URL: https://codereview.chromium.org/1223883002

Cr-Commit-Position: refs/heads/master@{#337377}

2 files changed, 16 insertions, 7 deletions

diff --git a/infra/scripts/legacy/site_config/config.py b/infra/scripts/legacy/site_config/config.py
index 0108e65..7c9ba9a 100644
--- a/infra/scripts/legacy/site_config/config.py
+++ b/infra/scripts/legacy/site_config/config.py
@@ -6,6 +6,7 @@
 """
 
 import os
+from twisted.spread import banana
 
 # DatabaseSetup was moved. Import it for backward compatibility
 from common.chromium_utils import DatabaseSetup  # pylint: disable=W0611
@@ -14,5 +15,18 @@ from config_bootstrap import Master # pylint: disable=W0403,W0611
 
 SITE_CONFIG_PATH = os.path.abspath(os.path.dirname(__file__))
 
+# By default, the banana's string size limit is 640kb, which is unsufficient
+# when passing diff's around. Raise it to 100megs. Do this here since the limit
+# is enforced on both the server and the client so both need to raise the
+# limit.
+banana.SIZE_LIMIT = 100 * 1024 * 1024
+
+
 def SiteConfigPath():
   return SITE_CONFIG_PATH
+
+
+
+
+
+
diff --git a/infra/scripts/runtest_wrapper.py b/infra/scripts/runtest_wrapper.py
index fe9835f..825a4ab 100755
--- a/infra/scripts/runtest_wrapper.py
+++ b/infra/scripts/runtest_wrapper.py
@@ -26,17 +26,12 @@ def main(argv):
   args = parser.parse_args(argv)
 
   env = copy.copy(os.environ)
-  # Reset PYTHONPATH to make sure we're not accidentally using
-  # the buildbot-provided value and build-side modules. That would make
-  # changes inside this directory not take effect on buildbot.
-  pythonpath = []
+  pythonpath = env.get('PYTHONPATH', '').split(':')
   pythonpath.append(os.path.join(
       SRC_DIR, 'infra', 'scripts', 'legacy', 'scripts'))
   pythonpath.append(os.path.join(
       SRC_DIR, 'infra', 'scripts', 'legacy', 'site_config'))
-  pythonpath.append(os.path.join(
-      SRC_DIR, 'third_party'))
-  env['PYTHONPATH'] = os.pathsep.join(pythonpath)
+  env['PYTHONPATH'] = ':'.join(pythonpath)
 
   return subprocess.call([
       sys.executable,