cmd/5g, cmd/6g, cmd/8g: remove width check for componentgen.
The move to 64-bit ints in 6g made componentgen ineffective.
In componentgen, the code already selects which values it can handle.
On amd64:
benchmark old ns/op new ns/op delta
BenchmarkBinaryTree17
9477970000 9582314000 +1.10%
BenchmarkFannkuch11
5928750000 5255080000 -11.36%
BenchmarkGobDecode
37103040 31451120 -15.23%
BenchmarkGobEncode
16042490 16844730 +5.00%
BenchmarkGzip
811337400 741373600 -8.62%
BenchmarkGunzip
197928700 192844500 -2.57%
BenchmarkJSONEncode
224164100 140064200 -37.52%
BenchmarkJSONDecode
258346800 231829000 -10.26%
BenchmarkMandelbrot200
7561780 7601615 +0.53%
BenchmarkParse
12970340 11624360 -10.38%
BenchmarkRevcomp
1969917000 1699137000 -13.75%
BenchmarkTemplate
296182000 263117400 -11.16%
R=nigeltao, dave, daniel.morsing
CC=golang-dev
https://golang.org/cl/
6821052