Auto merge of #122718 - workingjubilee:eyeliner-for-contrast, r=lcnr

Inline a bunch of trivial conditions in parser

It is often the case that these small, conditional functions, when inlined, reveal notable optimization opportunities to LLVM. While saethlin has done a lot of good work on making these kinds of small functions not need `#[inline]` tags as much, being clearer about what we want inlined will get both the MIR opts and LLVM to pursue it more aggressively.

On local perf runs, this seems fruitful. Let's see what rust-timer says.

r? `@ghost`

Author: bors