For MIPS's o32 ABI (REL), https://reviews.llvm.org/D19718 introduced
`OriginalAddend` to find the matching R_MIPS_LO16 relocation for
R_MIPS_GOT16 when STT_SECTION conversion is applicable.
lw $2, %lo(local1)
lui $2, %got(local1)
However, we could just store the original `Addend` in
`ELFRelocationEntry` and remove `OriginalAddend`.
Note: The relocation ordering algorithm in
https://reviews.llvm.org/D19718 is inefficient (#104562), which will be
addressed by another patch.
1a6bf94407