Localize Math.imul

[hjerabek]

I have been reading through the hash implementations you provide and I noticed that you often use Math.imul within the iteration step. You seem to be interested in high performance, so I presume you won't mind me suggesting the following (premature) optimization:

Localize imul (var imul=Math.imul) in all functions that use it in the loop. Otherwise, EVERY call to Math.imul in EVERY iteration step requires traversing the whole context tree (and checking every context for the Math property) up to the global scope, and then looking up the imul property.