$GOROOT/src/pkg/exp/html/testdata/go1.html is an execution of the
$GOROOT/doc/go1.html template by godoc.

Sample numbers on my linux,amd64 desktop:
BenchmarkParser	     500	   4699198 ns/op	  16.63 MB/s
--- BENCH: BenchmarkParser
        parse_test.go:409: 1 iterations, 14653 mallocs per iteration
        parse_test.go:409: 100 iterations, 14651 mallocs per iteration
        parse_test.go:409: 500 iterations, 14651 mallocs per iteration
BenchmarkRawLevelTokenizer	    2000	    904957 ns/op	  86.37 MB/s
--- BENCH: BenchmarkRawLevelTokenizer
        token_test.go:657: 1 iterations, 28 mallocs per iteration
        token_test.go:657: 100 iterations, 28 mallocs per iteration
        token_test.go:657: 2000 iterations, 28 mallocs per iteration
BenchmarkLowLevelTokenizer	    2000	   1134300 ns/op	  68.91 MB/s
--- BENCH: BenchmarkLowLevelTokenizer
        token_test.go:657: 1 iterations, 41 mallocs per iteration
        token_test.go:657: 100 iterations, 41 mallocs per iteration
        token_test.go:657: 2000 iterations, 41 mallocs per iteration
BenchmarkHighLevelTokenizer	    1000	   2096179 ns/op	  37.29 MB/s
--- BENCH: BenchmarkHighLevelTokenizer
        token_test.go:657: 1 iterations, 6616 mallocs per iteration
        token_test.go:657: 100 iterations, 6616 mallocs per iteration
        token_test.go:657: 1000 iterations, 6616 mallocs per iteration

R=rsc
CC=andybalholm, golang-dev, r
https://golang.org/cl/6257067