Revert "Remove GrDrawAtlasOp"

This reverts commit 97d957d1db657f8bbcec3db5fdddd5868ab9512e.

Reason for revert: Looking at perf, desktop GPUs get better, many mobile GPUs get worse.

Original change's description:
> Remove GrDrawAtlasOp
> 
> The base device turns drawAtlas into drawVertices, which ends
> up being *faster* (in my tests) than our specialized code.
> 
> It's certainly possible to write a custom version that's better,
> but for now, it seems better to just do this.
> 
> Bug: skia:
> Change-Id: I247f0c0a24fb21c8206f4e3ea9fecac85679ba73
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/203163
> Reviewed-by: Brian Salomon <bsalomon@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>

TBR=bsalomon@google.com,brianosman@google.com,reed@google.com

Change-Id: Idfb3dd7d33a3905644aafdefc99e7814b08d7c7b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/203053
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/tools/gpu/GrTest.cpp b/tools/gpu/GrTest.cpp
index ba5e40d..b8a743f 100644
--- a/tools/gpu/GrTest.cpp
+++ b/tools/gpu/GrTest.cpp
@@ -178,6 +178,7 @@
 DRAW_OP_TEST_EXTERN(EllipseOp);
 DRAW_OP_TEST_EXTERN(FillRectOp);
 DRAW_OP_TEST_EXTERN(GrAtlasTextOp);
+DRAW_OP_TEST_EXTERN(DrawAtlasOp);
 DRAW_OP_TEST_EXTERN(DrawVerticesOp);
 DRAW_OP_TEST_EXTERN(NonAALatticeOp);
 DRAW_OP_TEST_EXTERN(NonAAStrokeRectOp);
@@ -204,6 +205,7 @@
             DRAW_OP_TEST_ENTRY(EllipseOp),
             DRAW_OP_TEST_ENTRY(FillRectOp),
             DRAW_OP_TEST_ENTRY(GrAtlasTextOp),
+            DRAW_OP_TEST_ENTRY(DrawAtlasOp),
             DRAW_OP_TEST_ENTRY(DrawVerticesOp),
             DRAW_OP_TEST_ENTRY(NonAALatticeOp),
             DRAW_OP_TEST_ENTRY(NonAAStrokeRectOp),