time: fix grammar/spelling errors in test comment

Change-Id: I159bd1313e617c929008f6ac54ec7d702293360b
Reviewed-on: https://go-review.googlesource.com/57430Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/time/time_test.go

@@ -1203,8 +1203,8 @@ var defaultLocTests = []struct {
 }
 
 func TestDefaultLoc(t *testing.T) {
-	//This test verifyes that all Time's methods behaves identical if loc is set
-	//as nil or UTC
+	// Verify that all of Time's methods behave identically if loc is set to
+	// nil or UTC.
 	for _, tt := range defaultLocTests {
 		t1 := Time{}
 		t2 := Time{}.UTC()