[gtest] Fix building on OpenBSD/sparc64 (#145225)

Cherry pick a patch from 1.15.0

Add missing include for raise(3)

google/googletest@7f036c5

Author: brad0

third-party/unittest/googletest/src/gtest.cc

@@ -43,6 +43,7 @@
 #include <algorithm>
 #include <chrono>  // NOLINT
 #include <cmath>
+#include <csignal>
 #include <cstdint>
 #include <cstdlib>
 #include <cstring>