[llvm] [AArch64] Enable "sink-and-fold" in MachineSink by default (PR #67432)

[via llvm-commits]

bgra8 wrote:

@momchil-velikov this is causing a substantial compilation time regression when generating dwarf output. A V8 c++ file which compiles in less than 10s before this revision, compiles in 10 minutes at this revision.

The compilation command is something like:
```
clang
  -cc1 -triple aarch64-generic-linux-gnu -emit-obj \
  -debug-info-kind=constructor \
  -split-dwarf-file /tmp/repro.dwo \
  -split-dwarf-output /tmp/repro.dwo \
  -O3 -std=gnu++20 \
  -fsized-deallocation \
  -o /tmp/repro.o \
  -x c++ repro.cc
```

I started a reduction but it might take considerable time as we deal with such a high compilation time regression.

A revert will be welcome to unblock us before we come up with the reduced test case.

https://github.com/llvm/llvm-project/pull/67432