Clean up pyauto NaCl test logs
Clean up pyauto NaCl test logs

This patch cleans up the pyauto NaCl test logs by doing two things:

- Sets the chrome log level so that it only logs major failures. Doing
  this silences the numerous warnings from chrome that we are running
  without a sandbox (we know this) and that the chrome src directory
  could not be found (we know this too).

- Redirects the extremely verbose nexe output away from the console by
  modifying the NACL_EXE_STDOUT and NACL_EXE_STDERR environment
  variables. Note that if a nexe fails, we still explicitly log the
  contents of the page including any errors the nexe might have
  encountered.

BUG=nacl1870
TEST=scons pyauto_tests

Review URL: http://codereview.chromium.org/7078009

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@5509 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,nacl-webkit/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,nacl-webkit/native_client,nacl-webkit/native_client