[android] Don't write bytecode when running stack.

stack otherwise writes ".../stackc", which our gitignore can't
reasonably ignore.

Bug: 767620
Change-Id: I838e78488efa6c5c6847930d224ab930a0802438
Reviewed-on: https://chromium-review.googlesource.com/676729
Reviewed-by: Zhiling Huang <hzl@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#507386}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 8ddab7614bf8e067b30a427908a79828ed4b5db2

android/pylib/symbols/stack_symbolizer.py

@@ -92,10 +92,12 @@ class Symbolizer(object):
     if self._enable_relocation_packing and self._apk_libs:
       for apk_lib in self._apk_libs:
         cmd.extend(['--packed-lib', apk_lib])
+    env = dict(os.environ)
+    env['PYTHONDONTWRITEBYTECODE'] = '1'
     with tempfile.NamedTemporaryFile() as f:
       f.write('\n'.join(data_to_symbolize))
       f.flush()
-      _, output = cmd_helper.GetCmdStatusAndOutput(cmd + [f.name])
+      _, output = cmd_helper.GetCmdStatusAndOutput(cmd + [f.name], env=env)
     for line in output.splitlines():
       if not include_stack and 'Stack Data:' in line:
         break