cmd/go: linux 386+amd64 longtest builders not completing

[dmitshur]

From https://build.golang.org:

It appears that starting with commit f30044a (CL 248326), linux longtest builders are not making progress past cmd/fix tests:

##### Testing packages.
ok  	archive/tar	0.021s
ok  	archive/zip	23.818s
[...]
ok  	cmd/compile/internal/syntax	1.831s
ok  	cmd/compile/internal/test	0.004s [no tests to run]
ok  	cmd/compile/internal/types	0.003s
ok  	cmd/cover	0.749s
ok  	cmd/doc	0.119s
ok  	cmd/fix	0.423s
<stuck and no more progress past this point>

From looking at successful logs, the next package to be tested is cmd/go. The aforementioned CL touches something about parallelism in cmd/go, which might be affecting some tests that are not run with -short flag.

Note that the windows longtest builder is succeeding. Maybe the same test doesn't run there, or maybe it's something else.

I'll look into a creating a revert CL and see if linux longtest builders pass with it.

/cc @matloob

[gopherbot]

Change https://golang.org/cl/249017 mentions this issue: cmd/go: revert 3 CLs affecting par.Work, context propagation, tracing