[clang] Fix printf fixit for objc specific types

For the triple thumbv7-apple-ios8.0.0 ssize_t is long and size_t is unsigned long,
while NSInteger is int and NSUinteger is unsigned int. Following 
https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/Strings/Articles/formatSpecifiers.html
Clang catches it and insert a cast to long, for example
 printf("%zd", getNSInteger())
will be replaced with 
 printf("%zd", (long)getNSInteger())
but since the underlying type of ssize_t is long the specifier "%zd" is not getting replaced.
This diff changes this behavior to enable replacing the specifier "%zd" with the correct one.

Differential revision: https://reviews.llvm.org/D38159

Test plan: make check-all

llvm-svn: 314011