Like operator did not strip off quotes

[shijinglu]

1. Like operator did not strip off quotes
2. Right node of the like op should be a literal instead of an identity

@Override
    public void exitExprLikeOp(LureParser.ExprLikeOpContext ctx) {
        super.exitExprLikeOp(ctx);
        String leftIdentifier = ctx.expr().getText();
        String rightStrLiteral = ctx.TK_STRING_LITERAL().getText();
        if (rightStrLiteral.length() > 2) {
            rightStrLiteral = rightStrLiteral.substring(1, rightStrLiteral.length() - 1);
        }
        astMap.put(
                ctx,
                new NodeLike(
                        NodeIdentity.fromString(leftIdentifier),
                        NodeLiteral.fromString(rightStrLiteral),
                        null,
                        null,
                        null));
    }

[shijinglu]

test case:

expect(true, "country like `US*`", ctx);