[clang] Enable printf check for CFIndex

[clang] Enable printf check for CFIndex

According to
https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/Strings/Articles/formatSpecifiers.html
CFIndex and NSInteger should be treated the same way (see the section Platform Dependencies).
This diff changes the function shouldNotPrintDirectly in SemaChecking.cpp accordingly
and adds tests for the "fixit" and the warning.

Differential revision: https://reviews.llvm.org/D34496

Test plan: make check-all

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@306343 91177308-0d34-0410-b5e6-96231b3b80d8