Implements BigDecimal check in the JsonPrimitive.equals()

gson/src/main/java/com/google/gson/JsonPrimitive.java

@@ -291,14 +291,15 @@ public boolean equals(Object obj) {
           : this.getAsNumber().longValue() == other.getAsNumber().longValue();
     }
     if (value instanceof Number && other.value instanceof Number) {
+      if (value instanceof BigDecimal && other.value instanceof BigDecimal) {
+        // Uses compareTo to ignore scale of values, e.g. `0` and `0.00` should be considered equal
+        return this.getAsBigDecimal().compareTo(other.getAsBigDecimal()) == 0;
+      }
+
       double thisAsDouble = this.getAsDouble();
       double otherAsDouble = other.getAsDouble();
-
-      return (this.value instanceof BigDecimal && other.value instanceof BigDecimal)
-          // Uses compareTo to ignore scale of values, e.g. `0` and `0.00` should be considered equal
-          ? this.getAsBigDecimal().compareTo(other.getAsBigDecimal()) == 0
-          : thisAsDouble == otherAsDouble
-              || (Double.isNaN(thisAsDouble) && Double.isNaN(otherAsDouble));
+      // Don't use Double.compare(double, double) because that considers -0.0 and +0.0 not equal
+      return (thisAsDouble == otherAsDouble) || (Double.isNaN(thisAsDouble) && Double.isNaN(otherAsDouble));
     }
     return value.equals(other.value);
   }