Add emulation methods for ROR (immediate), ROR (register), and RRX.

Turns out that they can be funneled through the helper methods
EmulateShiftImm()/ EmulateShiftReg() as well.

Modify EmulateShiftImm() to handle SRType_ROR and SRType_RRX.
And fix a typo in the impl of utility Shift_C() in ARMUtils.h.

llvm-svn: 125689