[lld/ELF][X86] Respect outSecOff when checking if GOTPCREL can be relaxed (#86334)

The existing implementation didn't handle when the input text section
was some offset from the output section.

This resulted in an assert in relaxGot() with an lld built with asserts
for some large binaries, or even worse, a silently broken binary with an
lld without asserts.

(cherry picked from commit 48048051)