8266172: -Wstringop-overflow happens in vmError.cpp

Reviewed-by: dholmes, stuefe

src/hotspot/share/utilities/vmError.cpp

@@ -1770,8 +1770,8 @@ static void crash_with_sigfpe() {
 // crash with sigsegv at non-null address.
 static void crash_with_segfault() {
 
-  char* const crash_addr = (char*)VMError::segfault_address;
-  *crash_addr = 'X';
+  int* crash_addr = reinterpret_cast<int*>(VMError::segfault_address);
+  *crash_addr = 1;
 
 } // end: crash_with_segfault