go: x/playground: "timeout running program" error on official testable example

What version of Go are you using (go version)?

go1.14.2 on Go playground

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

Go playground

What did you do?

1. I tried to run the testable example on https://golang.org/pkg/net/http/httputil/#DumpResponse

and it failed immediately with the error “timeout running program”

1. I clicked the share button and I was redirected to https://play.golang.org/p/EULBr_niSNP

where the same code run successfully with out any errors

1. I changed the text in bold:

w.Header().Set(“Date”, “Wed, 19 Jul 1972 19:00:00 GMT”)

with random text just to have different code and clicked run again.

I tried the above multiple times:

Step 1 always fails Step 2 always runs successfully Step 3 sometimes fails and sometimes runs successfully

What did you expect to see?

Testable examples running successfully in all 3 cases described above

What did you see instead?