RFR 8232880: Update test documentation with additional settings for client UI tooltip tests

[Dmitry Markov]

Hello,

Could you review the fix for jdk14, please?

	bug: https://bugs.openjdk.java.net/browse/JDK-8232880 <https://bugs.openjdk.java.net/browse/JDK-8232880>
	webrev: http://cr.openjdk.java.net/~dmarkov/8232880/webrev.00/ <http://cr.openjdk.java.net/~dmarkov/8232880/webrev.00/>

Some Client UI tests use the following key sequence to show/hide tooltip message: “CTRL” + “F1". However this key combination is reserved by operating system on OS X platform. As a results the tests fail.
Test documentation should be updated with some notes regarding this.

Thanks,
Dmitry