[SPARK-13722][SQL] No Push Down for Non-deterministics Predicates through Generate

#### What changes were proposed in this pull request?

Non-deterministic predicates should not be pushed through Generate.

#### How was this patch tested?

Added a test case in `FilterPushdownSuite.scala`

Author: gatorsmile <gatorsmile@gmail.com>

Closes #11562 from gatorsmile/pushPredicateDownWindow.

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala

@@ -901,7 +901,7 @@ object PushPredicateThroughGenerate extends Rule[LogicalPlan] with PredicateHelp
       // Predicates that reference attributes produced by the `Generate` operator cannot
       // be pushed below the operator.
       val (pushDown, stayUp) = splitConjunctivePredicates(condition).partition { cond =>
-        cond.references subsetOf g.child.outputSet
+        cond.references.subsetOf(g.child.outputSet) && cond.deterministic
       }
       if (pushDown.nonEmpty) {
         val pushDownPredicate = pushDown.reduce(And)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/FilterPushdownSuite.scala

@@ -496,6 +496,24 @@ class FilterPushdownSuite extends PlanTest {
     comparePlans(optimized, correctAnswer)
   }
 
+  test("generate: non-deterministic predicate referenced no generated column") {
+    val originalQuery = {
+      testRelationWithArrayType
+        .generate(Explode('c_arr), true, false, Some("arr"))
+        .where(('b >= 5) && ('a + Rand(10).as("rnd") > 6))
+    }
+    val optimized = Optimize.execute(originalQuery.analyze)
+    val correctAnswer = {
+      testRelationWithArrayType
+        .where('b >= 5)
+        .generate(Explode('c_arr), true, false, Some("arr"))
+        .where('a + Rand(10).as("rnd") > 6)
+        .analyze
+    }
+
+    comparePlans(optimized, correctAnswer)
+  }
+
   test("generate: part of conjuncts referenced generated column") {
     val generator = Explode('c_arr)
     val originalQuery = {