sanitizer_common: make sem_trywait as non-blocking

[dvyukov]

Summary

sem_trywait never blocks.
Use REAL instead of COMMON_INTERCEPTOR_BLOCK_REAL.

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

if (res == 0) {
     COMMON_INTERCEPTOR_ACQUIRE(ctx, (uptr)s);
   }
   return res;
 }
 
 INTERCEPTOR(int, sem_trywait, __sanitizer_sem_t *s) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, sem_trywait, s);
-  int res = COMMON_INTERCEPTOR_BLOCK_REAL(sem_trywait)(s);
+  int res = REAL(sem_trywait)(s);
   if (res == 0) {
     COMMON_INTERCEPTOR_ACQUIRE(ctx, (uptr)s);
   }
   return res;
 }
 
 INTERCEPTOR(int, sem_timedwait, __sanitizer_sem_t *s, void *abstime) {
   void *ctx;