Calling quit() on FirefoxDriver doesn't release everything when marionette is disabled

[Toilal]

Meta -

OS: Windows 7

Selenium Version: 3.0.0-beta4

Browser: Firefox 46 (using FirefoxDriver with -Dwebdriver.firefox.marionette=false)

Browser Version: 46.0.1

Expected Behavior -

When calling quit() on FirefoxDriver instance, quit() method from underlying CommandExecutor instance should be invoked instance to release its resource like profile temporary directory.

Actual Behavior -

quit() is never invoked on the CommandExecutor instance.

Steps to reproduce -

Use the debugger, place a breakpoint in FirefoxDriver$LazyCommandExecutor#quit(), and invoke quit() on the FirefoxDriver instance. Breakpoint is not hit, and temporary directory from Firefox profile is not deleted until the JVM is shutdown.

Problem is that RemoveWebDriver invoke stopClient() without arguments, but this method is not overriden in FirefoxDriver. Only stopClient(Capabilities desiredCapabilities, Capabilities requiredCapabilities) is overriden.