Add support for EnableDependentJoins for Impala data sources

Hi,
Request to Add support for EnableDependentJoins for Impala data sources. Current docs only suggest [0] [1] Table 13.8
[0]
For sources that support temporary tables (DB2, Derby, H2, HSQL 2.0+, MySQL 5.0+, Oracle, PostgreSQL, SQLServer, Sybase) allow dependent join pushdown.

[1]
https://access.redhat.com/documentation/en-US/Red_Hat_JBoss_Data_Virtualization/6.2/html/Development_Guide_Volume_3_Reference_Material/sect-JDBC_Translator.html
Thanks