Faster load/store arm64
Faster load/store arm64

The load/store code is optimized to make better use of the offsets
present in the load/store instructions.
Also use GOT reloc's instead of ABS64 relocs.

arm64-gen.c/arm64_check_offset:
- New function to split offset used by load/store and by arm64_sym.

arm64-gen.c/arm64_sym:
- Use GOT reloc's instead of ABS64 relocs.

arm64-gen.c/load arm64-gen.c/store:
- Use new arm64_check_offset function.

arm64-gen.c/gen_bounds_prolog arm64-gen.c/gen_bounds_epilog:
- Use GOT reloc's instaed of ABS64 relocs.

mingodad/tinycc,mirror/tinycc,mirror/tinycc,mirror/tinycc,mingodad/tinycc,mingodad/tinycc,mingodad/tinycc,mirror/tinycc