swift234

Devirtualize in the performance inliner.

Attempt to devirtualize any apply that we come across in the performance
inliner prior to attempting to inline.

The is the first step of getting the inliner/specializer/devirtualizer
working together so that we can converge on high quality code with less
work.

Although this is not meant to directly improve performance, but rather
be a step towards converging to high quality code with fewer passes,
because it alters what gets inlined when, it did have a (mostly)
positive effect on performance.

These are some of the larger deltas I see, where the percentage is
percentage speed-up, and negative percentages indicate a slow-down.

-O:
---
BenchLangCallingCFunction         16.7%
CaptureProp                       17.1%
Sim2DArray                        22.0%

-Ounchecked
-----------
BenchLangCallingCFunction        -11.2%
QuickSort                         39.4%
SwiftStructuresBubbleSort        -26.7%

Swift SVN r26728