[SPARK-7142] [SQL] Minor enhancement to BooleanSimplification Optimizer rule....

[SPARK-7142] [SQL] Minor enhancement to BooleanSimplification Optimizer rule. Incorporate review comments

Adding changes suggested by cloud-fan  in #5700

cc marmbrus

Author: Yash Datta <Yash.Datta@guavus.com>

Closes #8716 from saucam/bool_simp.

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

@@ -435,10 +435,10 @@ object BooleanSimplification extends Rule[LogicalPlan] with PredicateHelper {
         // a && a  =>  a
         case (l, r) if l fastEquals r => l
         // a && (not(a) || b) => a && b
-        case (l, Or(l1, r)) if (Not(l) fastEquals l1) => And(l, r)
-        case (l, Or(r, l1)) if (Not(l) fastEquals l1) => And(l, r)
-        case (Or(l, l1), r) if (l1 fastEquals Not(r)) => And(l, r)
-        case (Or(l1, l), r) if (l1 fastEquals Not(r)) => And(l, r)
+        case (l, Or(l1, r)) if (Not(l) == l1) => And(l, r)
+        case (l, Or(r, l1)) if (Not(l) == l1) => And(l, r)
+        case (Or(l, l1), r) if (l1 == Not(r)) => And(l, r)
+        case (Or(l1, l), r) if (l1 == Not(r)) => And(l, r)
         // (a || b) && (a || c)  =>  a || (b && c)
         case _ =>
           // 1. Split left and right to get the disjunctive predicates,