cmd/go: convert TestGoGenerateBadImports to script framework

Part of converting all tests to script framework to improve
test parallelism.

Updates #36320
Updates #17751

Change-Id: Id1afafad2063d917fd55e08f0725ce3e93201c35
Reviewed-on: https://go-review.googlesource.com/c/go/+/212878
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

src/cmd/go/go_test.go

@@ -2738,20 +2738,6 @@ func TestGoGenerateXTestPkgName(t *testing.T) {
 	}
 }
 
-func TestGoGenerateBadImports(t *testing.T) {
-	if runtime.GOOS == "windows" {
-		t.Skip("skipping because windows has no echo command")
-	}
-
-	// This package has an invalid import causing an import cycle,
-	// but go generate is supposed to still run.
-	tg := testgo(t)
-	defer tg.cleanup()
-	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata"))
-	tg.run("generate", "gencycle")
-	tg.grepStdout("hello world", "go generate gencycle did not run generator")
-}
-
 func TestGoGetCustomDomainWildcard(t *testing.T) {
 	testenv.MustHaveExternalNetwork(t)
 	testenv.MustHaveExecPath(t, "git")

src/cmd/go/testdata/script/generate_bad_imports.txt

+[windows] skip # skip because windows has no echo command
+
+go generate gencycle
+stdout 'hello world' # check go generate gencycle ran the generator
+
+-- gencycle/gencycle.go --
+//go:generate echo hello world
+
+package gencycle
+
+import _ "gencycle"

src/cmd/go/testdata/src/gencycle/gencycle.go

-//go:generate echo hello world
-
-package gencycle
-
-import _ "gencycle"