[AArch64][GISel] and+or+shl => bfi

This fixes a GISEL vs SDAG regression that showed up at -Os in 256.bzip2

In `_getAndMoveToFrontDecode`:

gisel:
```
and w9, w0, #0xff
orr w9, w9, w8, lsl #8
```

sdag:
```
bfi w0, w8, #8, #24
```

Differential revision: https://reviews.llvm.org/D103291