cmd/compilebench: change MakeBash to StdCmd

Instead of running make.bash, run 'go build -a std cmd'.
Change the benchmark name to reflect this.

This does roughly the same task, namely compile and link
all the code in the tree, but with several advantages:

* It works cross-platform.
* It is a bit faster, while measuring the same fundamentals.
* It doesn't measure how fast the bootstrap compiler works,
  which is irrelevant.
* If interrupted, it leaves the current Go installation
  in a usable state.

Change-Id: I469b1d032b48b06e3dea021bd031283bc3a16ff4
Reviewed-on: https://go-review.googlesource.com/39714
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
1 file changed