Skip likely numerically unstable test

Author: bdlucas1

test/builtin/drawing/doc_tests.yaml

@@ -110,8 +110,11 @@ doc-051:
     expr: Plot3D[Exp[x] Cos[y], {x, -2, 1}, {y, -Pi, 2 Pi}]
 doc-052:
     expr: Plot3D[Log[x + y^2], {x, -1, 1}, {y, -1, 1}]
+# skipping following due to significant numerical diff btw macos and ubuntu
+# i think the test is unstable because of the / (x y)
 doc-053:
     expr: Plot3D[Sin[x y] /(x y), {x, -3, 3}, {y, -3, 3}, Mesh->All]
+    skip: true
 doc-054:
     expr: Plot3D[Sin[x y], {x, -2, 2}, {y, -2, 2}, Mesh->Full]
 doc-055: