Check if JIT is able to hoist these "constants" outside the loop.

[CarlVerret]

I guess the JIT isn't able to hoist these "constants" outside the loop. As the caller is also guarded by #if HAS_INTRINSICS you could hoist these manually, and pass them in as arguments. Results in tighter code here, and should give a (little) perf-boost, as it's a loop body.

Originally posted by @gfoidl in https://github.com/CarlVerret/csFastFloat/pull/91#discussion_r732602453