[lld] [lld][ELF] Support relax R_LARCH_ALIGN (PR #78692)

[Xi Ruoyao via llvm-commits]

xry111 wrote:

I'd suggest make some tests to see if `--gc-section` works with relaxation.  In the BFD linker we found `--gc-section` is somehow broken now with relaxation :(

https://github.com/llvm/llvm-project/pull/78692