[lld] [lld][ELF][LoongArch] Support relaxing R_LARCH_CALL36 (PR #127312)

[WÁNG Xuěruì via llvm-commits]

xen0n wrote:

cc @SixWeining @wangleiat @xry111 -- sorry for being a 鸽子 and delaying this optimization sooooo long; Real Life hits hard. I have finished the implementation back in April 2024 as you can see in the commit details, but only got time to finish the test case just now.

https://github.com/llvm/llvm-project/pull/127312