swift234

Don't inline into thunks, except very small functions.

rdar://problem/19701613

Code size reductions (negative means less code size):
bin/PerfTests_O:  -3.7%
bin/PerfTests_Ounchecked:  -1.9%
bin/PerfTests_Onone:  +0.2%
stdlib/core/macosx/Swift.o:  -2.2%

The -2.2% in Swift.o constitutes of about +5% in specializations and -11% in protocoll witnesses in the dylib.
(-> still room for improvement regarding specializations)

Note that completely disabling inlining into thunks (even small functions) would increase the code size.

There is litte change in performance, a few + and - within 10%.
Beyond this there is (+ means faster):
Phonebook@O: +26%
ImageProc@Ounchecked: +14%
StringWalk@Ounchecked: -16%




Swift SVN r25001