[AArch64] Refactor the loads and stores optimizer
[AArch64] Refactor the loads and stores optimizer

Move remaining inline matching of instructions of some optimizations into
separate functions, like in the other optimizations.  Otherwise, NFC.

Differential revision: https://reviews.llvm.org/D40090

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@318335 91177308-0d34-0410-b5e6-96231b3b80d8

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