misc/benchcmp: don't require "Benchmark" at beginning of line
misc/benchcmp: don't require "Benchmark" at beginning of line

Output is package_name.BenchmarkXXX.

R=rsc
CC=golang-dev
http://codereview.appspot.com/5440123

tv42/old-go,dsriram/golang,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,pombredanne/go-deleteme,apparentlymart/golang,gnanderson/go,apparentlymart/golang,pombredanne/go-deleteme,tv42/old-go,dsriram/golang,apparentlymart/golang,dsriram/golang,dsriram/golang,pombredanne/go-deleteme,dsriram/golang,pombredanne/go-deleteme,gnanderson/go,apparentlymart/golang,gnanderson/go,apparentlymart/golang,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,apparentlymart/golang,gnanderson/go,gnanderson/go,gnanderson/go,dsriram/golang,tv42/old-go,gnanderson/go,dsriram/golang,tv42/old-go