cmd/go: TestDefaultGOPATH failures

[gopherbot]

#!watchflakes
default <- pkg == "cmd/go" && test == "TestDefaultGOPATH"

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestDefaultGOPATH
=== PAUSE TestDefaultGOPATH
=== CONT  TestDefaultGOPATH
    go_test.go:1235: running testgo [env GOPATH]
    go_test.go:1235: standard output:
    go_test.go:1235: /Users/swarming/.swarming/w/ir/x/t/cmd-go-test-765590296/gotest3021853762/home/go
        
    go_test.go:1239: running testgo [env GOPATH]
    go_test.go:1239: standard output:
    go_test.go:1239: 
        
    go_test.go:1239: go [env GOPATH] failed unexpectedly in /Users/swarming/.swarming/w/ir/x/w/goroot/src/cmd/go: exec: WaitDelay expired before I/O complete
--- FAIL: TestDefaultGOPATH (64.09s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "cmd/go" && test == "TestDefaultGOPATH"

2025-12-12 17:04 go1.26-darwin-amd64-race release-branch.go1.26@e8a83788 cmd/go.TestDefaultGOPATH (log)

=== RUN   TestDefaultGOPATH
=== PAUSE TestDefaultGOPATH
=== CONT  TestDefaultGOPATH
    go_test.go:1235: running testgo [env GOPATH]
    go_test.go:1235: standard output:
    go_test.go:1235: /Users/swarming/.swarming/w/ir/x/t/cmd-go-test-765590296/gotest3021853762/home/go
        
    go_test.go:1239: running testgo [env GOPATH]
    go_test.go:1239: standard output:
    go_test.go:1239: 
        
    go_test.go:1239: go [env GOPATH] failed unexpectedly in /Users/swarming/.swarming/w/ir/x/w/goroot/src/cmd/go: exec: WaitDelay expired before I/O complete
--- FAIL: TestDefaultGOPATH (64.09s)

— watchflakes