[JITLink][LoongArch] Support R_LARCH_ALIGN relaxation (#122259)
Linker relaxation is not implemented for jitlink now. But if
relaxation is enabled by clang, R_LARCH_RELAX and
R_LARCH_ALIGN relocations will be emitted.
This commit adapts lld's algorithm to jitlink. Currently, only
relaxing R_LARCH_ALIGN is implemented. Other relaxable
relocs can be implemented in the future.
Without this, interpreting C++ code using clang-repl or running
ir using lli when relaxation is enabled will occur error: `JIT
session error: Unsupported loongarch relocation:102: R_LARCH_ALIGN`.
Similar to https://github.com/llvm/llvm-project/commit/310473c536dd4837934832d1b5454d212f15d5cc but only implement align.