Handle issue in eq and neq when any of params is null (#552)

Fixes regression made by 59bd121

Closes #551

We have observed that while evaluating neq or eq, the second param might be null. After #498 it started causing NullPointerException so I made a special check for that. Additionally, I allowed the first param to be nullable as well.

android/src/main/java/com/swmansion/reanimated/nodes/OperatorNode.java

@@ -189,6 +189,9 @@ public boolean eval(Double x, Double y) {
   private static final Operator EQ = new CompOperator() {
     @Override
     public boolean eval(Double x, Double y) {
+      if (x == null || y == null) {
+        return x == y;
+      }
       return x.doubleValue() == y.doubleValue();
     }
   };
@@ -213,6 +216,9 @@ public boolean eval(Double x, Double y) {
   private static final Operator NEQ = new CompOperator() {
     @Override
     public boolean eval(Double x, Double y) {
+      if (x == null || y == null) {
+        return x == y;
+      }
       return x.doubleValue() != y.doubleValue();
     }
   };