testing: print cpu type as label for benchmarks
Supports 386 and amd64 architectures on all operating systems.
Example output:
$ go test -bench=.*
goos: darwin
goarch: amd64
pkg: strconv
cpu: Intel(R) Core(TM) i7-3520M CPU @ 2.90GHz
BenchmarkAtof64Decimal-4
24431032 46.8 ns/op
...
As the displayed CPU information is only used for information
purposes it is lazily initialized when needed using the new
internal/sysinfo package.
This allows internal/cpu to stay without dependencies and avoid
initialization costs when the CPU information is not needed as
the new code to query the CPU name in internal/cpu can be
dead code eliminated if not used.
Fixes #39214
Change-Id: I77ae5c5d2fed6b28fa78dd45075f9f0a6a7f1bfd
Reviewed-on: https://go-review.googlesource.com/c/go/+/263804
Trust: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Keith Randall <khr@golang.org>