tests: Use MakeUnique to construct objects owned by unique_ptrs

src/test/test_bitcoin_fuzzy.cpp

@@ -279,7 +279,7 @@ static int test_one_input(std::vector<uint8_t> buffer) {
 
 static std::unique_ptr<ECCVerifyHandle> globalVerifyHandle;
 void initialize() {
-    globalVerifyHandle = std::unique_ptr<ECCVerifyHandle>(new ECCVerifyHandle());
+    globalVerifyHandle = MakeUnique<ECCVerifyHandle>();
 }
 
 // This function is used by libFuzzer