correcting when the trace log is made
TEIID-2580 fix for nillable elements
TEIID-2581 fix for empty proc vararg call
TEIID-2580 expanding the fix to xpathvalue
TEIID-2582 ensuring that using the calling thread does not unnecessarily
use the output buffer
Merge branch '8.4.x' of https://github.com/teiid/teiid