Add an assertion to check that Chrome/Breakpad does not install a signal handler

src/native_client/src/trusted/service_runtime/win/nacl_signal.c

Index: src/native_client/src/trusted/service_runtime/win/nacl_signal.c
diff --git a/src/native_client/src/trusted/service_runtime/win/nacl_signal.c b/src/native_client/src/trusted/service_runtime/win/nacl_signal.c
index 97ca8b8920b8771b74b5401f115823fb200e2aef..a24f96d1aab8019ba1bdb102f2bd3b50e06c1128 100644
--- a/src/native_client/src/trusted/service_runtime/win/nacl_signal.c
+++ b/src/native_client/src/trusted/service_runtime/win/nacl_signal.c
@@ -131,3 +131,10 @@ void NaClSignalHandlerFiniPlatform(void) {
   /* Remove our old catch if there is one, this allows us to add again */
   if (NULL != s_VEH) RemoveVectoredExceptionHandler(s_VEH);
 }
+
+void NaClSignalAssertNoHandlers() {
+  /*
+   * Windows has no direct equivalent of Unix signal handlers.  There
+   * is no interface for checking that no fault handlers are registered.
+   */
+}