Fix a microbenchmark crash on mingw32; seemingly %lld is not universally
supported on Windows, and %I64d is recommended instead.

R=csilvers
DELTA=6  (5 added, 0 deleted, 1 changed)


Revision created by MOE tool push_codebase.
MOE_MIGRATION=1034


git-svn-id: https://snappy.googlecode.com/svn/trunk@18 03e5f5b5-db94-4691-08a0-1a8bf15f6143
1 file changed