Processes prefix declarations in queries. This method collects all
prefixes that are declared in the supplied query, verifies that prefixes
are not redefined and replaces any
ASTQName nodes in the query
with equivalent
ASTIRI nodes.
Parameters: qc - The query that needs to be processed. A map containing the prefixes that are declared in the query (key)and the namespace they map to (value). throws: MalformedQueryException - If the query contains redefined prefixes or qnames that useundefined prefixes.