Disable WebRequest::SSL::Ignore unit test under AppVeyor

This test sporadically fails in builds with different compilers (both
MSVC and gcc) there for unknown reasons. Until we can find, and fix, the
underlying problem, disable this test to avoid spurious CI failures.

tests/net/webrequest.cpp

@@ -336,6 +336,16 @@ TEST_CASE_METHOD(RequestFixture,
     if (!InitBaseURL())
         return;
 
+    // For some reason this test sporadically fails under AppVeyor, so don't
+    // run it there.
+#ifdef __WINDOWS__
+    if ( IsAutomaticTest() )
+    {
+        WARN("Skipping DisablePeerVerify() test known to sporadically fail.");
+        return;
+    }
+#endif // __WINDOWS__
+
     CreateAbs("https://self-signed.badssl.com/");
     request.DisablePeerVerify();
     Run(wxWebRequest::State_Completed, 200);