Optimize literal storage.

[zherczeg]

3K binary size reduction 156K -> 153K (1600 lines removed, 700 added)

Benchmark	Perf (sec)
3d-cube.js	1.146 -> 1.141 : +0.506%
3d-raytrace.js	1.317 -> 1.250 : +5.094%
access-binary-trees.js	0.674 -> 0.631 : +6.318%
access-fannkuch.js	2.847 -> 2.847 : +0.005%
access-nbody.js	1.387 -> 1.319 : +4.907%
bitops-3bit-bits-in-byte.js	0.631 -> 0.636 : -0.765%
bitops-bits-in-byte.js	0.917 -> 0.928 : -1.162%
bitops-bitwise-and.js	1.923 -> 1.510 : +21.463%
bitops-nsieve-bits.js	2.243 -> 2.227 : +0.718%
controlflow-recursive.js	0.475 -> 0.462 : +2.736%
crypto-aes.js	1.244 -> 1.229 : +1.252%
crypto-md5.js	0.844 -> 0.818 : +3.068%
crypto-sha1.js	0.790 -> 0.769 : +2.632%
date-format-tofte.js	1.018 -> 0.917 : +9.907%
date-format-xparb.js	0.553 -> 0.503 : +9.121%
math-cordic.js	1.666 -> 1.624 : +2.565%
math-partial-sums.js	0.986 -> 0.874 : +11.285%
math-spectral-norm.js	0.699 -> 0.672 : +3.820%
string-base64.js	2.244 -> 2.165 : +3.521%
string-fasta.js	2.123 -> 1.995 : +6.031%
Geometric mean:	+4.799%

[LaszloLango]

LGTM

[zherczeg]

@franc0is After this change the snapshot only stores raw strings and numbers, so changing the magic strings or introducing (removing) string types do not affect the snapshot version.

[dbatyai]

LGTM