Description of problem:

A regression was found for an enhancement originally introduced in 6.3.4. 

According to TEIID-4543, parsing a date or time from a string column using the PARSEDATE or PARSETIME functions should be pushed as simple cast in case the format string is the standard value ('yyyy-MM-dd' and 'hh:mm:ss' respectively).

However, running e.g.

    SELECT IntKey FROM Source.SmallA WHERE PARSEDATE(StringKey, 'yyyy-MM-dd') = {d'2016-12-19'}

with 6.4 ER2 shows the following in the query plan:

   AccessNode(0) output=[Source.smalla.intkey] SELECT g_0.intkey AS c_0 FROM Source.smalla AS g_0 WHERE convert(parsetimestamp(g_0.stringkey, 'yyyy-MM-dd'), date) = {d'2016-12-19'} LIMIT 100
  

i.e. there is still the call to parsetimestamp function.