[Driver][X86] Support branch align options with LTO

Summary: Before this patch, we use two different ways to pass options to align branch
depending on whether LTO is enabled. For example, `-mbranches-within-32B-boundaries`
w/o LTO and `-Wl,-plugin-opt=-x86-branches-within-32B-boundaries` w/ LTO.  It's
inconvenient, so this patch unifies the way: we only need to pass options like
`-mbranches-within-32B-boundaries` to align branches, no matter LTO is enabled or not.

Differential Revision: https://reviews.llvm.org/D80289