runtime: more detail for crash_test.go

This updates the testcase to display the timestamps for the
runtime.a, it dependent packages atomic.a and sys.a, and
source files.

Change-Id: Id2901b4e8aa8eb9775c4f404ac01cc07b394ba91
Reviewed-on: https://go-review.googlesource.com/37332
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/runtime/crash_test.go

@@ -170,6 +170,9 @@ func checkStaleRuntime(t *testing.T) {
 				t.Logf("go list -f {{.StaleReason}} failed: %v", err)
 			}
 			t.Logf("go list -f {{.StaleReason}} runtime:\n%s", out)
+			out, err = testEnv(exec.Command("ls", "-lR", "--full-time", runtime.GOROOT())).CombinedOutput()
+			t.Logf("%s", out)
+
 			staleRuntimeErr = fmt.Errorf("Stale runtime.a. Run 'go install runtime'.")
 		}
 	})