[lang2/macro] fix some success tests

lang2/macro/tests/ui/pass/03-incrementer-contract.rs

@@ -18,7 +18,7 @@ mod incrementer {
         by: i32,
     }
 
-    impl Flipper {
+    impl Incrementer {
         #[ink(constructor)]
         fn new(&mut self, init_value: i32) {
             self.value.set(init_value as i64);

lang2/macro/tests/ui/pass/04-erc20-contract.rs

@@ -32,7 +32,7 @@ mod erc20 {
         amount: Balance,
     }
 
-    impl Flipper {
+    impl Erc20 {
         #[ink(constructor)]
         fn new(&mut self, initial_supply: Balance) {
             let caller = self.env().caller();