Revise comparison function in no-over-optimization tests. (#3742)

Apply the suggested fix to
conformance/uniforms/no-over-optimization-on-uniform-array-* tests to
use a scale factor in the comparison function instead of a fixed
constant.

Fixes #3738.

Author: kenrussell

sdk/tests/js/tests/no-over-optimizations-on-uniform-array.js

@@ -206,9 +206,9 @@ function testUniformOptimizationIssues(test) {
         gl.uniform4fv(locations[ii], [ii + 4, ii + 2, ii + 3, ii + 1]);
     }
 
-    var kEpsilon = 0.01;
+    var kEpsilon = Math.pow(2, -10);
     var isSame = function(v1, v2) {
-        return Math.abs(v1 - v2) < kEpsilon;
+        return Math.abs(v1 - v2) < Math.abs(v1) * kEpsilon;
     };
 
     for (var ii = 0; ii < test.maxUniformVectors; ++ii) {