Call lld with --pack-dyn-relocs=none if my_pack_module_relocations is false

* Factor out the logic that sets up my_pack_module_relocations
  from dynamic_binary.mk to pack_dyn_relocs_setup.mk.
* Use stand-alone relocation_packer only if my_pack_module_relocations
  is true and my_use_clang_lld is false.

Bug: 80093890
Bug: 73768157
Test: build and boot with USE_CLANG_LLD=true
Change-Id: I7c4b5fcdce0754c57cff4acf86185cac65a26c40