[LLDB][ObjectFileELF] Support LoongArch64 in ApplyReloctions

Currently ApplyReloctions() deals with different archs' relocation types
together (in a single `switch() {..}`). I think it is incorrect because
different relocation types of different archs may have same enum values.

For example:
`R_LARCH_32` and `R_X86_64_64` are both `1`;
`R_LARCH_64` and `R_X86_64_PC32` are both `2`.

This patch handles each arch in seperate `switch()` to solve the enum
values conflict issue.

And a new test is added for LoongArch64.

Reviewed By: DavidSpickett

Differential Revision: https://reviews.llvm.org/D145462