Make test valid for backspace/delete

I noticed this test taking a very long time (10 seconds). The test as
written is invalid because the loop has a timeout with hitting the
exit condition.

The "a" is never inserted into the text box (at least on gtk3), so the
sending of back space appears to work when it didn't

Author: jonahgraham

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

@@ -5877,6 +5877,8 @@ public void test_backspaceAndDelete() {
 		}
 	}
 
+	assertEquals(1, text.getText().length());
+
 	// Simulate the backspace, ensuring that the caret is in the correct position
 	text.invokeAction(ST.DELETE_PREVIOUS);
 

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

@@ -1575,6 +1575,8 @@ public void test_backspaceAndDelete() {
 		}
 	}
 
+	assertEquals(1, text.getText().length());
+
 	display.post(backspace);
 	display.post(backspaceUp);