[sanitizer_common] Fix type in format specifier by casting

40dcf24 had changed the format
specifier to fix the build for their local system. Unfortunately,
that disagrees with some other systems, such as this buildbot:
https://lab.llvm.org/buildbot/#/builders/37/builds/30440

This patch fixes the issue for all systems by casting.

Author: thurstond

compiler-rt/lib/sanitizer_common/tests/sanitizer_bitvector_test.cpp

@@ -71,7 +71,7 @@ void Print(const set<uptr> &s) {
 #if defined(_WIN64)
     fprintf(stderr, "%llu ", *it);
 #else
-    fprintf(stderr, "%lu ", *it);
+    fprintf(stderr, "%lu ", (unsigned long)*it);
 #endif
   }
   fprintf(stderr, "\n");