swift234

[arc-analysis] Add two functions for applying canUseValue and canDecrementValue to a contiguous range of instructions in the same BB.

The two functions are:

1. valueHasARCUsesInInstructionRange.
2. valueHasARCDecrementsInInstructionRange.

They operate on the range [Start, End).

I am going to use them in enum simplification and sil code motion.

Swift SVN r19893