Bug 314847 Command parameters are never cleared
tests/org.eclipse.e4.core.commands.tests/src/org/eclipse/e4/core/commands/tests/HandlerTest.java
assertFalse(handler.q1);
		assertFalse(handler.q2);
		ECommandService cs = (ECommandService) workbenchContext
				.get(ECommandService.class.getName());
		ParameterizedCommand cmd = cs.createCommand(TEST_ID1, null);
		assertTrue(hs.canExecute(cmd));
		assertFalse(handler.q2);
		assertEquals(Boolean.TRUE, hs.executeHandler(cmd));
		assertTrue(handler.q1);
		assertTrue(handler.q2);
	}
	public void testDeactivateHandler() throws Exception {
		EHandlerService hs = (EHandlerService) workbenchContext
				.get(EHandlerService.class.getName());
		CallHandler handler = new CallHandler();
		hs.activateHandler(TEST_ID1, handler);
		assertFalse(handler.q1);
		assertFalse(handler.q2);
		ECommandService cs = (ECommandService) workbenchContext
				.get(ECommandService.class.getName());
		ParameterizedCommand cmd = cs.createCommand(TEST_ID1, null);
		assertTrue(hs.canExecute(cmd));
		assertFalse(handler.q2);
		hs.deactivateHandler(TEST_ID1, handler);
		assertNull(hs.executeHandler(cmd));
		assertTrue(handler.q1);
		assertFalse(handler.q2);
	}
	public void testActiveHandlerExecuteWorkbench() throws Exception {
		IEclipseContext c1 = workbenchContext.createChild("c1");