cmd/go: remove script.sh in TestTestCacheInputs

Updates #22593

Change-Id: I76e52dc8b874da13ae9e2d80e5c0d6d8424b67db
Reviewed-on: https://go-review.googlesource.com/83257
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/go/go_test.go

@@ -5150,6 +5150,7 @@ func TestTestCacheInputs(t *testing.T) {
 	tg.setenv("GOCACHE", tg.path("cache"))
 
 	defer os.Remove(filepath.Join(tg.pwd(), "testdata/src/testcache/file.txt"))
+	defer os.Remove(filepath.Join(tg.pwd(), "testdata/src/testcache/script.sh"))
 	tg.must(ioutil.WriteFile(filepath.Join(tg.pwd(), "testdata/src/testcache/file.txt"), []byte("x"), 0644))
 	old := time.Now().Add(-1 * time.Minute)
 	tg.must(os.Chtimes(filepath.Join(tg.pwd(), "testdata/src/testcache/file.txt"), old, old))