test: Add _win32_seterrormode.fail.cpp to silence Exception diaalogs on Windows desktop.

test/_win32_seterrormode.fail.cpp

@@ -0,0 +1,15 @@
+#include <windows.h>
+
+namespace {
+
+  class Win32ctor {
+  public:
+    Win32ctor() {
+      SetErrorMode(SEM_FAILCRITICALERRORS |
+                   SEM_NOGPFAULTERRORBOX |
+                   SEM_NOOPENFILEERRORBOX);
+    }
+  };
+
+  static Win32ctor ctor;
+}

test/lit.cfg

@@ -68,7 +68,7 @@ class LibcxxTestFormat(lit.formats.FileBasedTest):
             exec_file.close()
 
             try:
-                compile_cmd = [self.cxx_under_test, '-o', exec_path,
+                compile_cmd = [self.cxx_under_test, 'e:/llvm/libcxx/test/_win32_seterrormode.fail.cpp', '-o', exec_path,
                        source_path] + self.cpp_flags + self.ld_flags
                 cmd = compile_cmd
                 out, err, exitCode = self.execute_command(cmd)