feat(compile): remove table overhead for better performance

[nullchilly]

Problem: { string.byte } is only faster if we re-use the table a lot

Solution: Remove table caching

The definition for pairs is function pairs(t) return next, t, nil end so we have another small optimization to use next, t instead of pairs(t)

Benchmark was done on both the main and perf branch:

branch	time (ms)
main	0.3883049273
perf	0.0047219172