Add psqlODBC tests for sys.decimal and numeric (babelfish-for-postgre…

…sql#754)

This commit adds the sys.decimal and numeric tests for psqlODBC. It adds
the following test cases:

Table Creation
Failed Table Creation
Insert Valid Values
Insert Invalid Values
Update Valid Values
Update Invalid Values
Table View
Primary Key
Unique Constraint
Composite Keys
Arithmetic Operators
Comparison Operators

Task: BABELFISH-554, 592
Signed-off-by: Favian (Ian) Samatha ians@bitquilltech.com