Add browser regression test for calling evaluate requiring event loop

Regression test for
eclipse-platform#1771

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java

@@ -429,6 +429,27 @@ public void test_evalute_Cookies () {
 	assertFalse(res.isEmpty());
 }
 
+@Test
+public void test_evaluate_callingIntoSwt() throws Exception {
+	AtomicBoolean initialLoad = new AtomicBoolean();
+	AtomicBoolean openWindowListenerCalled = new AtomicBoolean();
+	browser.addProgressListener(ProgressListener.completedAdapter(e -> initialLoad.set(true)));
+	browser.addOpenWindowListener(event -> {
+		event.required = true; // block default
+		openWindowListenerCalled.set(true);
+	});
+	browser.setText("""
+			<button id="button" onClick="window.open('https://eclipse.org');">open eclipse.org</button>
+			""");
+	waitForPassCondition(initialLoad::get);
+
+	browser.evaluate("""
+				document.getElementById("button").click();
+			""");
+
+	waitForPassCondition(openWindowListenerCalled::get);
+}
+
 @Test
 public void test_ClearAllSessionCookies () {
 	// clearSessions will only work for Webkit2 when >= 2.16