[compiler-rt] [AArch64][compiler-rt] Add memcpy, memset, memmove, memchr builtins. (PR #77496)

[Stephen Tozer via llvm-commits]

SLTozer wrote:

As mentioned above this seems to be breaking buildbots, e.g. https://lab.llvm.org/buildbot/#/builders/275/builds/3646

https://github.com/llvm/llvm-project/pull/77496