Improve resolve reference.

[zherczeg]

Simple patch, but 17% improvement on bitops-bitwise-and.js.

Benchmark	Perf (sec)
3d-cube.js	0.950 -> 0.944 : +0.690%
3d-raytrace.js	1.132 -> 1.115 : +1.506%
access-binary-trees.js	0.588 -> 0.582 : +1.004%
access-fannkuch.js	2.371 -> 2.361 : +0.424%
access-nbody.js	1.070 -> 1.065 : +0.491%
bitops-3bit-bits-in-byte.js	0.582 -> 0.582 : +0.003%
bitops-bits-in-byte.js	0.869 -> 0.868 : +0.059%
bitops-bitwise-and.js	1.142 -> 0.938 : +17.802%
bitops-nsieve-bits.js	1.810 -> 1.800 : +0.545%
controlflow-recursive.js	0.401 -> 0.380 : +5.430%
crypto-aes.js	1.140 -> 1.114 : +2.210%
crypto-md5.js	0.753 -> 0.734 : +2.542%
crypto-sha1.js	0.714 -> 0.696 : +2.495%
date-format-tofte.js	0.879 -> 0.866 : +1.455%
date-format-xparb.js	0.476 -> 0.456 : +4.267%
math-cordic.js	1.351 -> 1.319 : +2.370%
math-partial-sums.js	0.723 -> 0.692 : +4.258%
math-spectral-norm.js	0.598 -> 0.584 : +2.307%
string-base64.js	2.075 -> 2.050 : +1.179%
string-fasta.js	1.814 -> 1.763 : +2.820%
Geometric mean:	+2.772%

[dbatyai]

LGTM

[LaszloLango]

LGTM