Bug 511874 temporarily disable test_execute_and_closeListener osx/win32

This test seems to be inconsistent on Cocoa and Win32.
It may be an issue with the test itself.

For now, I'm making this test only run on webkit*

I will setup a Cocoa/Win32 box to investigate this after vacation in 2
weeks. For now to prevent build log errors, I'll turn the test off.

Change-Id: I40e2ad2ff8afcfe0efa5e47f080e46312aee0f8f
Signed-off-by: Leo Ufimtsev <lufimtse@redhat.com>
diff --git a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java
index ec92ca3..f95c9fc 100644
--- a/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java
+++ b/tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java
@@ -15,6 +15,7 @@
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.junit.Assume.assumeFalse;
+import static org.junit.Assume.assumeTrue;
 
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -686,7 +687,8 @@
  */
 @Test
 public void test_execute_and_closeListener () {
-	// This test appears to be failing only on OSX.
+	String skipMsg = "This test is unstable on Cocoa/Win32 at present. Skipping test on non webkit2 for now. To be fixed in Bug 511874";
+	assumeTrue(skipMsg, isWebkit1 || isWebkit2);
 	// See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=511874
 
 	AtomicBoolean hasClosed = new AtomicBoolean(false);