Fix crash in NSValue.isEqual() when it is passed an NSNumber (#619)

NSNumbers are not added to the side table, so we can't find them.

Author: gribozavr

Foundation/NSValue.swift

@@ -58,10 +58,12 @@ open class NSValue : NSObject, NSCopying, NSSecureCoding, NSCoding {
             } else {
                 // bypass _concreteValue accessor in order to avoid acquiring lock twice
                 let (lhs, rhs) = NSValue.SideTableLock.synchronized {
-                    return (NSValue.SideTable[ObjectIdentifier(self)]!,
-                            NSValue.SideTable[ObjectIdentifier(object)]!)
+                    return (NSValue.SideTable[ObjectIdentifier(self)],
+                            NSValue.SideTable[ObjectIdentifier(object)])
+                }
+                if let lhs = lhs, let rhs = rhs {
+                    return lhs.isEqual(rhs)
                 }
-                return lhs.isEqual(rhs)
             }
         }
         return false

TestFoundation/TestNSValue.swift

@@ -29,6 +29,7 @@ class TestNSValue : XCTestCase {
             ( "test_valueWithShortArray", test_valueWithShortArray ),
             ( "test_valueWithULongLongArray", test_valueWithULongLongArray ),
             ( "test_valueWithCharPtr", test_valueWithULongLongArray ),
+            ( "test_isEqual", test_isEqual ),
         ]
     }
 
@@ -126,4 +127,11 @@ class TestNSValue : XCTestCase {
         NSValue(bytes: &charPtr, objCType: "*").getValue(&expectedPtr)
         XCTAssertEqual(charPtr, expectedPtr)
     }
+
+    func test_isEqual() {
+        let number = NSNumber(value: Int(123))
+        var long: Int32 = 123456
+        let value = NSValue(bytes: &long, objCType: "l")
+        XCTAssertFalse(value.isEqual(number))
+    }
 }