[dev.ssa] cmd/compile: run std tests with SSA codegen as part of all.bash

[dev.ssa] cmd/compile: run std tests with SSA codegen as part of all.bash

Todd Neal has made all the stdlib tests pass.
Now the trybots and build dashboard can
help us keep them passing.

All of this code will be unwound bit by bit
as SSA matures and then becomes the default.

Change-Id: I52ac7e72a87d329ccce974d6671c054374828d11
Reviewed-on: https://go-review.googlesource.com/14294
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>