Improve global object setup and access performance

[lahma]

Going through GlobalEnvironmentRecord and optimizing it a bit. Biggest change is to remove ObjectEnvironmentRecord as intermediary abstraction for global access and replace with faster patterns.

[lahma]

Esprima.Benchmark.SunSpiderBenchmark

Diff	Method	FileName	Mean	Error	Allocated
Old	Run	3d-cube	208.56 ms	1.151 ms	51123.86 KB
New			193.96 ms (-7%)	0.613 ms	50173.23 KB (-2%)
Old	Run	3d-morph	158.67 ms	0.466 ms	49744.51 KB
New			158.57 ms (0%)	0.431 ms	48381.13 KB (-3%)
Old	Run	3d-raytrace	165.48 ms	0.402 ms	93386.96 KB
New			170.51 ms (+3%)	0.309 ms	92704.3 KB (-1%)
Old	Run	access-binary-trees	85.50 ms	0.189 ms	78471.05 KB
New			83.33 ms (-3%)	0.179 ms	75722.18 KB (-4%)
Old	Run	access-fannkuch	450.41 ms	3.388 ms	135.64 KB
New			453.33 ms (+1%)	0.894 ms	134.92 KB (-1%)
Old	Run	access-nbody	188.00 ms	0.346 ms	63848.88 KB
New			191.20 ms (+2%)	0.355 ms	63844.97 KB (0%)
Old	Run	access-nsieve	159.94 ms	0.443 ms	21518.15 KB
New			155.83 ms (-3%)	0.322 ms	21518.29 KB (0%)
Old	Run	bitop(...)-byte [24]	157.57 ms	0.187 ms	68949.06 KB
New			157.90 ms (0%)	0.389 ms	68948.59 KB (0%)
Old	Run	bitops-bits-in-byte	250.52 ms	0.450 ms	45445.25 KB
New			232.01 ms (-7%)	0.338 ms	45447.46 KB (0%)
Old	Run	bitops-bitwise-and	183.40 ms	0.913 ms	93438.89 KB
New			144.90 ms (-21%)	0.297 ms	55938.59 KB (-40%)
Old	Run	bitops-nsieve-bits	209.32 ms	0.824 ms	54854.94 KB
New			209.42 ms (0%)	0.894 ms	54075.9 KB (-1%)
Old	Run	contr(...)rsive [21]	115.48 ms	0.253 ms	124116.86 KB
New			108.79 ms (-6%)	0.233 ms	108772.05 KB (-12%)
Old	Run	crypto-aes	138.69 ms	0.330 ms	15570.65 KB
New			140.10 ms (+1%)	0.259 ms	14945.07 KB (-4%)
Old	Run	crypto-md5	106.71 ms	0.305 ms	95412.42 KB
New			103.07 ms (-3%)	0.274 ms	88403.25 KB (-7%)
Old	Run	crypto-sha1	107.37 ms	0.292 ms	82071.72 KB
New			107.27 ms (0%)	1.078 ms	75069.09 KB (-9%)
Old	Run	date-format-tofte	101.71 ms	0.138 ms	46360.64 KB
New			101.47 ms (0%)	0.332 ms	45251.01 KB (-2%)
Old	Run	date-format-xparb	61.16 ms	0.134 ms	29412.61 KB
New			61.54 ms (+1%)	0.083 ms	28787.24 KB (-2%)
Old	Run	math-cordic	345.85 ms	1.011 ms	123970.21 KB
New			334.87 ms (-3%)	0.578 ms	113033.16 KB (-9%)
Old	Run	math-partial-sums	140.30 ms	0.329 ms	68948.38 KB
New			129.37 ms (-8%)	0.221 ms	50094.8 KB (-27%)
Old	Run	math-spectral-norm	135.45 ms	0.361 ms	67174.92 KB
New			130.40 ms (-4%)	0.370 ms	63333.36 KB (-6%)
Old	Run	regexp-dna	114.35 ms	0.605 ms	17672.22 KB
New			108.88 ms (-5%)	0.411 ms	17667.62 KB (0%)
Old	Run	string-base64	111.62 ms	0.331 ms	12525.78 KB
New			104.61 ms (-6%)	0.265 ms	11241.36 KB (-10%)
Old	Run	string-fasta	208.05 ms	0.334 ms	167274.79 KB
New			200.99 ms (-3%)	0.472 ms	155489.57 KB (-7%)
Old	Run	string-tagcloud	74.83 ms	0.519 ms	48438.33 KB
New			73.19 ms (-2%)	0.247 ms	48439.01 KB (0%)
Old	Run	string-unpack-code	78.00 ms	0.153 ms	84571.22 KB
New			76.52 ms (-2%)	0.101 ms	83958.43 KB (-1%)
Old	Run	strin(...)input [21]	85.57 ms	1.059 ms	44618.85 KB
New			83.10 ms (-3%)	0.307 ms	41619.18 KB (-7%)

Jint.Benchmark.StopwatchBenchmark

Diff	Method	Mean	Error	Allocated
Old	Jint_ParsedScript	527.4 ms	1.74 ms	226.59 MB
New		400.7 ms (-24%)	1.11 ms	107.13 MB (-53%)