Further reduction of GPU workload in shapes benchmarks. Hopefully this squelches the random crashes on Mali 400.

BUG=skia:4937
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1703233002

Review URL: https://codereview.chromium.org/1703233002
diff --git a/bench/ShapesBench.cpp b/bench/ShapesBench.cpp
index 07f7d56..2266cc3 100644
--- a/bench/ShapesBench.cpp
+++ b/bench/ShapesBench.cpp
@@ -263,15 +263,15 @@
 
 // Large primitives (GPU bound, in theory):
 DEF_BENCH(return new ShapesBench(ShapesBench::kRect_ShapesType, ShapesBench::kNone_ShapesType,
-                                 1000, SkISize::Make(500, 500), false);)
+                                 100, SkISize::Make(500, 500), false);)
 DEF_BENCH(return new ShapesBench(ShapesBench::kOval_ShapesType, ShapesBench::kNone_ShapesType,
-                                 1000, SkISize::Make(500, 500), false);)
+                                 100, SkISize::Make(500, 500), false);)
 DEF_BENCH(return new ShapesBench(ShapesBench::kOval_ShapesType, ShapesBench::kNone_ShapesType,
-                                 1000, SkISize::Make(500, 501), false);)
+                                 100, SkISize::Make(500, 501), false);)
 DEF_BENCH(return new ShapesBench(ShapesBench::kRRect_ShapesType, ShapesBench::kNone_ShapesType,
-                                 1000, SkISize::Make(500, 500), false);)
+                                 100, SkISize::Make(500, 500), false);)
 DEF_BENCH(return new ShapesBench(ShapesBench::kMixed_ShapesType, ShapesBench::kNone_ShapesType,
-                                 1000, SkISize::Make(500, 501), false);)
+                                 100, SkISize::Make(500, 501), false);)
 
 // Donuts (small and large). These fall-back to path rendering due to non-orthogonal rotation
 // making them quite slow. Thus, reduce the counts substantially: