Allow previously-hoisted layers to be reused in the same draw

Allow previously-hoisted layers to be reused in the same draw

In the Sierpinkski test case there are only a few layers appear in the "to be drawn" lists but they those layers get reused a lot of times with different transforms. This CL adds an additional category to allow such layers to be placed in the GrReplacements object without needing to be rendered.

This is split out of (Fix sub-picture layer rendering bugs - https://codereview.chromium.org/597293002/)

BUG=skia:2315
R=bsalomon@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/616023002