[MC][X86] Disable branch align in non-text section

Summary:
The instruction in non-text section can not be executed, so they will not affect performance.
In addition, their encoding values are treated as data, so we should not touch them.

Reviewers: MaskRay, reames, LuoYuanke, jyknight

Reviewed By: MaskRay

Subscribers: annita.zhang, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77971