Fix memcheck_test failure with GLibC.
Fix memcheck_test failure with GLibC.

With a stripped libvalgrind.so Valgrind reports look slightly different. This
change relaxes test patterns to match both old and new reports.
Review URL: http://codereview.chromium.org/7281028

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@5867 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

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