Batch multiple single NVPR draw paths to instanced draws

Batch multiple single NVPR draw paths to instanced draws.
A draw path batch can be combined to other batch if the
batches do not overlap and have same draw characteristics.

Join the batches in linked list and flatten the list to a
path list during draw time.

Replace GrPathRendering::drawPath with GrPathRendering::drawPaths.

Perf changes ARM, Shield TV device, Tegra X1 GPU:
                desk_chalkboard.skp_1	21.5ms -> 17.8ms	0.83x
                    desk_mapsvg.skp_1	7.49ms -> 6.18ms	0.82x
Others results are more volatile.
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1908433002

Review URL: https://codereview.chromium.org/1908433002
9 files changed