Remove more tests from the NaCl SCons build.

Remove more tests from the NaCl SCons build.

 * pnacl_test_example was a smoke test that broke in revision r161425.

 * browser_startup_time was a performance test that needs to be redone to work on the Chrome bots.

 * stress_many_nexes was a manual test.

BUG= http://code.google.com/p/chromium/issues/detail?id=154400

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=162173

[Mark Seaborn, 2012-10-12 22:00:48]

LGTM when the bots pass

https://codereview.chromium.org/11145002/diff/12/ppapi/native_client/tests/na...
File ppapi/native_client/tests/nacl_browser/browser_startup_time/nacl.scons
(left):

https://codereview.chromium.org/11145002/diff/12/ppapi/native_client/tests/na...
ppapi/native_client/tests/nacl_browser/browser_startup_time/nacl.scons:25:
'${SCONSTRUCT_DIR}/tools/process_perf_output.py')),
Will you also remove the process_perf*.py scripts?

[jvoung - send to chromium..., 2012-10-12 23:37:06]

https://codereview.chromium.org/11145002/diff/12/ppapi/native_client/tests/na...
File ppapi/native_client/tests/nacl_browser/pnacl_client_translator/nacl.scons
(right):

https://codereview.chromium.org/11145002/diff/12/ppapi/native_client/tests/na...
ppapi/native_client/tests/nacl_browser/pnacl_client_translator/nacl.scons:41:
'pnacl_test_example_obj.bc',
You can substitute a fairly arbitrary .bc file for this (vs a .pexe), so that
linking fails.

[Nick Bray, 2012-10-15 23:22:38]

PTAL, the bots are being pretty slow but I tested the fix locally.  I added
program_fragment.cc to make PNaCl's bad pexe tests hermetic.

[jvoung (off chromium), 2012-10-15 23:28:52]

LGTM thanks!

[commit-bot: I haz the power, 2012-10-16 15:59:09]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ncbray@chromium.org/11145002/12002

[commit-bot: I haz the power, 2012-10-16 18:09:22]

Change committed as 162173