LibJS/Bytecode: Add support for direct eval()

This is implemented as a special mode of the Call opcode that invokes
the PerformEval AO (instead of the Call or Construct AO).

Userland/Libraries/LibJS/Bytecode/Op.h

@@ -714,6 +714,7 @@ public:
     enum class CallType {
         Call,
         Construct,
+        DirectEval,
     };
 
     Call(CallType type, Register callee, Register this_value, Optional<StringTableIndex> expression_string = {})