Googletest export

Avoid segfault on null premature_exit_filepath.

PiperOrigin-RevId: 395965853

googletest/src/gtest.cc

@@ -5038,7 +5038,7 @@ class ScopedPrematureExitFile {
       // create the file with a single "0" character in it.  I/O
       // errors are ignored as there's nothing better we can do and we
       // don't want to fail the test because of this.
-      FILE* pfile = posix::FOpen(premature_exit_filepath, "w");
+      FILE* pfile = posix::FOpen(premature_exit_filepath_.c_str(), "w");
       fwrite("0", 1, 1, pfile);
       fclose(pfile);
     }