[SwitchLowering] Handle multiple destinations on condensed case stmts

Switch cases statements with sequential values that branch to the same
destination BB may often be handled together in a single new source BB.
In this scenario we need to remove remaining incoming values from PHI
instructions in the destination BB, as to match the number of source
branches.

Differential Revision: http://reviews.llvm.org/D6415

rdar://problem/19040894
[LICM] Store sink and indirectbr instructions

Loop simplify skips exit-block insertion when exits contain indirectbr
instructions. This leads to an assertion in LICM when trying to sink
stores out of non-dedicated loop exits containing indirectbr
instructions. This patch fix this issue by re-checking for dedicated
exits in LICM prior to store sink attempts.

Differential Revision: http://reviews.llvm.org/D6414

rdar://problem/18943047