Revert "[CodeGen] -fsanitize=alignment: add cl::opt sanitize-alignment-builtin...

Revert "[CodeGen] -fsanitize=alignment: add cl::opt sanitize-alignment-builtin to disable memcpy instrumentation (#69240)"

This reverts commit e8fe4de6.

memcpy/memmove instrumentation for -fsanitize=alignment has been tested
on a huge code base. There were some cleanups but the number does not
justify a workaround.