Enum panic test for pre-byzantium.

test/libsolidity/semanticTests/enums/enum_explicit_overflow_homestead.sol

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+contract test {
+    enum ActionChoices {GoLeft, GoRight, GoStraight}
+
+    constructor() {}
+
+    function getChoiceExp(uint256 x) public returns (uint256 d) {
+        choice = ActionChoices(x);
+        d = uint256(choice);
+    }
+
+    function getChoiceFromSigned(int256 x) public returns (uint256 d) {
+        choice = ActionChoices(x);
+        d = uint256(choice);
+    }
+
+    function getChoiceFromNegativeLiteral() public returns (uint256 d) {
+        choice = ActionChoices(-1);
+        d = uint256(choice);
+    }
+
+    ActionChoices choice;
+}
+
+// ====
+// EVMVersion: <byzantium
+// compileViaYul: also
+// ----
+// getChoiceExp(uint256): 3 -> FAILURE # These should throw #
+// getChoiceFromSigned(int256): -1 -> FAILURE
+// getChoiceFromNegativeLiteral() -> FAILURE
+// getChoiceExp(uint256): 2 -> 2 # These should work #
+// getChoiceExp(uint256): 0 -> 0