Revert "Tweak Plot size to try to get better perf."

This reverts commit fdcbe206f52a95eed5f97cc47d2a0801a4a7ee8e.

Reason for revert: Produced a further perf regression.

Original change's description:
> Tweak Plot size to try to get better perf.
> 
> Large plots allow tighter packing of large glyphs, but smaller plots
> take less time to update. Trying a size in between for the largest
> A8 size.
> 
> Bug: skia:8642
> Change-Id: Ib6d7651b70fe3a2101a3bfc5b367c433123cb914
> Reviewed-on: https://skia-review.googlesource.com/c/179242
> Commit-Queue: Jim Van Verth <jvanverth@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

TBR=jvanverth@google.com,robertphillips@google.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: skia:8642
Change-Id: I9bc32abfae1fb4a6380b2fd5c0a1ea269447c534
Reviewed-on: https://skia-review.googlesource.com/c/179726
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
diff --git a/tests/DrawOpAtlasTest.cpp b/tests/DrawOpAtlasTest.cpp
index b1d30ac..52fd9c0 100644
--- a/tests/DrawOpAtlasTest.cpp
+++ b/tests/DrawOpAtlasTest.cpp
@@ -266,17 +266,17 @@
     test_atlas_config(reporter, 65536, 4 * 1024 * 1024, kARGB_GrMaskFormat,
                       { 1024, 1024 }, { 256, 256 });
     test_atlas_config(reporter, 65536, 4 * 1024 * 1024, kA8_GrMaskFormat,
-                      { 2048, 2048 }, { 512, 256 });
+                      { 2048, 2048 }, { 512, 512 });
     // 8 MB
     test_atlas_config(reporter, 65536, 8 * 1024 * 1024, kARGB_GrMaskFormat,
                       { 2048, 1024 }, { 256, 256 });
     test_atlas_config(reporter, 65536, 8 * 1024 * 1024, kA8_GrMaskFormat,
-                      { 2048, 2048 }, { 512, 256 });
+                      { 2048, 2048 }, { 512, 512 });
     // 16 MB (should be same as 8 MB)
     test_atlas_config(reporter, 65536, 16 * 1024 * 1024, kARGB_GrMaskFormat,
                       { 2048, 1024 }, { 256, 256 });
     test_atlas_config(reporter, 65536, 16 * 1024 * 1024, kA8_GrMaskFormat,
-                      { 2048, 2048 }, { 512, 256 });
+                      { 2048, 2048 }, { 512, 512 });
 
     // 4MB, restricted texture size
     test_atlas_config(reporter, 1024, 8 * 1024 * 1024, kARGB_GrMaskFormat,