[TSAN] Relax the expected output of race_on_mutex.c

[TSAN] Relax the expected output of race_on_mutex.c

The stack trace produced by TSan on MIPS is:

  Previous write of size 8 at 0x0120ed2930 by thread T1:
    #0 memset
/home/slt/LLVM/llvm/projects/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc:678
(race_on_mutex.c.tmp+0x0120071808)
    #1 __GI___pthread_mutex_init
/build/glibc-g99ldr/glibc-2.19/nptl/pthread_mutex_init.c:84
(libpthread.so.0+0x000000d634)
    #2 <null>
/home/slt/LLVM/llvm/projects/compiler-rt/test/tsan/race_on_mutex.c:11 (race_on_mutex.c.tmp+0x01200ea59c)

Reviewers: samsonov, dvyukov
Subscribers: llvm-commits, mohit.bhakkad, jaydeep
Differential: http://reviews.llvm.org/D17796
llvm-svn: 263778