[AArch64][SVE] Add instcombine for PTEST_ANY(X=OP(PG,...), X) -> PTEST_ANY(PG, X))

Given this is an OR reduction the two are equivalent and later
optimizations (AArch64InstrInfo::optimizePTestInstr) may rewrite the
sequence to use the flag-setting variant of instruction X, to remove the
PTEST altogether.

Reviewed By: paulwalker-arm, bsmith

Differential Revision: https://reviews.llvm.org/D134946