cmd/go: convert TestPackageNotStaleWithTrailingSlash to script framework

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

Updates #36320
Updates #17751

Change-Id: I1020feaa4ddb40ff52c46728bc4973cea4c7b066
Reviewed-on: https://go-review.googlesource.com/c/go/+/214391
Reviewed-by: Jay Conrod <jayconrod@google.com>

Author: matloob

src/cmd/go/go_test.go

@@ -1151,25 +1151,6 @@ func TestPackageMainTestCompilerFlags(t *testing.T) {
 	tg.grepStderr(`([\\/]compile|gccgo).* (-p p1|-fgo-pkgpath=p1).*p1\.go`, "should have run compile -p p1 p1.go")
 }
 
-// Issue 12690
-func TestPackageNotStaleWithTrailingSlash(t *testing.T) {
-	skipIfGccgo(t, "gccgo does not have GOROOT")
-	tg := testgo(t)
-	defer tg.cleanup()
-
-	// Make sure the packages below are not stale.
-	tg.wantNotStale("runtime", "", "must be non-stale before test runs")
-	tg.wantNotStale("os", "", "must be non-stale before test runs")
-	tg.wantNotStale("io", "", "must be non-stale before test runs")
-
-	goroot := runtime.GOROOT()
-	tg.setenv("GOROOT", goroot+"/")
-
-	tg.wantNotStale("runtime", "", "with trailing slash in GOROOT, runtime listed as stale")
-	tg.wantNotStale("os", "", "with trailing slash in GOROOT, os listed as stale")
-	tg.wantNotStale("io", "", "with trailing slash in GOROOT, io listed as stale")
-}
-
 // Issue 4104.
 func TestGoTestWithPackageListedMultipleTimes(t *testing.T) {
 	tooSlow(t)

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

@@ -0,0 +1,13 @@
+# Tests Issue #12690
+
+[gccgo] skip 'gccgo does not have GOROOT'
+
+! stale runtime
+! stale os
+! stale io
+
+env GOROOT=$GOROOT'/'
+
+! stale runtime
+! stale os
+! stale io