Handle type coercion for the arguments of function

[grieve54706]

SQL parser parses the statement with the function pg_relation_size and will return the argument as LongLiteral. And the expression is transferred to BIGINT via ExpressionTypeAnalyzer. But we define the function pg_relation_size is with INTEGER.

• TestFunctions.testJdbcQuery[select pg_get_expr('test', 1)]