vcl: merge DrawPolyLineDirect() and drawPolyLineDirectNoAACheck()

I've merged these two functions, I just added a new function parameter to switch on and off
the AA check, this function parameter defaults to false so DrawPolyLineDirect needs to do the
AA check each time. If bBypassAACheck is set to true, then we automatically enable AA.

Change-Id: Id2d9b2036a41716590f7b87f658f5bb210964392
Reviewed-on: https://gerrit.libreoffice.org/12191
Reviewed-by: Chris Sherlock <chris.sherlock79@gmail.com>
Tested-by: Chris Sherlock <chris.sherlock79@gmail.com>