[BOLT] Change order of new sections

[BOLT] Change order of new sections

While the order of new sections in the output binary was deterministic
in the past (i.e. there was no run-to-run variation), it wasn't always
rational as we used size to define the precedence of allocatable
sections within "code" or "data" groups (probably unintentionally).
Fix that by defining stricter section-ordering rules.

Other than the order of sections, this should be NFC.

Reviewed By: rafauler

Differential Revision: https://reviews.llvm.org/D135235