Previously`InX::Got` and InX::MipsGot synthetic sections
were not removed if ElfSym::GlobalOffsetTable was defined.
ElfSym::GlobalOffsetTable is a symbol for _GLOBAL_OFFSET_TABLE_.
Patch moves ElfSym::GlobalOffsetTable check out from removeUnusedSyntheticSections.
Also note that there was no point to check ElfSym::GlobalOffsetTable for MIPS case
because InX::MipsGot::empty() always returns false for non-relocatable case, and in case
of relocatable output we do not create special symbols anyways.
Instead of adding more and more comments, you want to rewrite in most cases: We need to emit a GOT even if it's empty if there's a relocation that is relative to GOT (such as GOTOFFREL) or there's a symbol that points to a GOT (i.e. _GLOBAL_OFFSET_TABLE_).