StdlibUnittest: prevent abort dialog on Windows

Adjust the abort behaviour on Windows.  The aborts would cause a large
number of dialogs to appear.  This reduces the load a bit and is crucial
for getting tests to run without manual intervention.

Author: compnerd

stdlib/private/StdlibUnittest/InterceptTraps.cpp

@@ -19,6 +19,7 @@
 #if defined(_WIN32)
 #include <io.h>
 #include <process.h>
+#include <stdlib.h>
 #endif
 
 #include "swift/Runtime/Config.h"
@@ -50,6 +51,10 @@ void installTrapInterceptor() {
   // Disable buffering on stdout so that everything is printed before crashing.
   setbuf(stdout, 0);
 
+#if defined(_WIN32)
+  _set_abort_behavior(1, _WRITE_ABORT_MSG);
+#endif
+
   signal(SIGILL,  CrashCatcher);
   signal(SIGABRT, CrashCatcher);
   signal(SIGFPE,  CrashCatcher);