Pal: Increase the stream counter in the ssrHandlingLoop.

The ssrHandlingLoop path currently lacks a way to secure
the stream handle, which causes invalid stream handles to
be dereferenced in the ssrHandling path.
To prevent any race situations, increasing the stream counter
in the ssrHandlingLoop route

Change-Id: I1bbc64094aceed2c5e2d151fd641b6cabdbd9723