re PR go/89406 (Go testing leaves many temporary directories in /tmp around)

PR go/89406
    go/internal/gccgoimporter: remove temporary directories in test
    
    Backport of https://golang.org/cl/164862.
    
    Updates https://gcc.gnu.org/PR89406
    
    Reviewed-on: https://go-review.googlesource.com/c/164863

From-SVN: r269338

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-a72eca1f435002076655fd6a54ce869ac39856dc
+decbbfb563ecf4609a3148dc789ae77ab1c62768
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/go/internal/gccgoimporter/importer_test.go

@@ -143,17 +143,21 @@ func TestObjImporter(t *testing.T) {
 	}
 	t.Logf("gccgo version %d.%d", major, minor)
 
-	tmpdir, err := ioutil.TempDir("", "")
+	tmpdir, err := ioutil.TempDir("", "TestObjImporter")
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer os.RemoveAll(tmpdir)
+
 	initmap := make(map[*types.Package]InitData)
 	imp := GetImporter([]string{tmpdir}, initmap)
 
-	artmpdir, err := ioutil.TempDir("", "")
+	artmpdir, err := ioutil.TempDir("", "TestObjImporter")
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer os.RemoveAll(artmpdir)
+
 	arinitmap := make(map[*types.Package]InitData)
 	arimp := GetImporter([]string{artmpdir}, arinitmap)
 
@@ -198,8 +202,4 @@ func TestObjImporter(t *testing.T) {
 			t.Fatal(err)
 		}
 	}
-
-	if err = os.Remove(tmpdir); err != nil {
-		t.Fatal(err)
-	}
 }