[lld/elf] support quote usage in section names

Section names used in ELF linker scripts can be quoted, but such
quotes must not be propagated to the binary ELF section names.  As
such strip the quotes from the section names when processing them, and
also strip them from linker script functions that take section names
as parameters.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D124266