Work around b/24465209, do not pack relocation table.

Global flag --pack-dyn-relocs=android is used with clang lld.
For b/24465209, we need to override that with pack_relocations:false.

Bug: 24465209
Bug: 80093890
Test: build with USE_CLANG_LLD=true and run dlext.compat_elf_hash_and_relocation_tables
Change-Id: I9364feb4070d4f75705d8651d535c792fe6ad6f7