Fix (band-aid) Go/JavaScript cross-boundary error transformation

bug_test.go

@@ -10,7 +10,7 @@ func Test_262(t *testing.T) {
 
 	test := runTest()
 	test(`raise:
-        42 = 42;
+        eval("42 = 42;");
     `, "ReferenceError: Invalid left-hand side in assignment")
 }
 

builtin.go

@@ -17,8 +17,12 @@ func builtinGlobal_eval(call FunctionCall) Value {
 	}
 	program, err := parse(toString(source))
 	if err != nil {
-		//panic(call.runtime.newError("SyntaxError", UndefinedValue()))
-		panic(&_syntaxError{Message: fmt.Sprintf("%v", err)})
+		switch err := err.(type) {
+		case *_syntaxError, *_error, _error:
+			panic(err)
+		default:
+			panic(&_syntaxError{Message: fmt.Sprintf("%v", err)})
+		}
 	}
 	runtime := call.runtime
 	if call.evalHint {

otto_test.go

@@ -209,7 +209,7 @@ func Test_eval(t *testing.T) {
 	`, "true")
 	// TODO Make this a sane result
 	// Lightning bolt, lightning bolt, lightning bolt, ...
-	test(`ghi`, "SyntaxError: SyntaxError: SyntaxError: Unexpected token ILLEGAL ()")
+	test(`ghi`, "SyntaxError: Unexpected token ILLEGAL ()")
 
 	test(`
         function abc(){

runtime.go

@@ -208,7 +208,7 @@ func (self *_runtime) tryEvaluate(inner func() Value) (tryValue Value, throw boo
 				return
 			case *_syntaxError:
 				throw = true
-				throwValue = toValue(self.newError("SyntaxError", toValue(caught.String())))
+				throwValue = toValue(self.newError("SyntaxError", toValue(caught.Message)))
 				return
 			}
 			panic(caught)