This patch adds a command line option to list the checkers that were enabled
by analyzer-checker and not disabled by -analyzer-disable-checker.

It can be very useful to debug long command lines when it is not immediately
apparent which checkers are turned on and which checkers are turned off.

Differential Revision: https://reviews.llvm.org/D23060


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@278006 91177308-0d34-0410-b5e6-96231b3b80d8