Add gc percent test in lrucache to prevent cheating

lrucache/cache_test.go

@@ -132,6 +132,11 @@ func TestCache_eviction(t *testing.T) {
 	}
 }
 
+func TestCache_GCPercent(t *testing.T) {
+	var p = debug.SetGCPercent(100)
+	require.Equal(t, p, 100)
+}
+
 func BenchmarkCache_Set(b *testing.B) {
 	for _, tc := range []struct {
 		name string