[X86]Support options -mno-gather -mno-scatter

[X86]Support options -mno-gather -mno-scatter

Gather instructions could lead to security issues, details please refer to https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/gather-data-sampling.html.
This supported options -mno-gather and -mno-scatter, which could avoid generating gather/scatter instructions in backend except using intrinsics or inline asms.

Reviewed By: pengfei

Differential Revision: https://reviews.llvm.org/D157680