JS: Implement Long.hashCode function.

#KT-13756 Fixed

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/NumberTest.java

@@ -81,6 +81,10 @@ public final class NumberTest extends SingleFileTranslationTest {
         checkFooBoxIsOk();
     }
 
+    public void testLongHashCode() throws Exception {
+        checkFooBoxIsOk();
+    }
+
     public void testLongArray() throws Exception {
        checkFooBoxIsOk();
     }

js/js.translator/testData/long.js

@@ -279,6 +279,10 @@
              this.getLowBitsUnsigned();
     };
 
+    /** @return {number} The 32-bit hashCode of this value. */
+    Kotlin.Long.prototype.hashCode = function() {
+      return this.high_ ^ this.low_;
+    };
 
     /**
      * @param {number=} opt_radix The radix in which the text should be written.

js/js.translator/testData/number/cases/longHashCode.kt

@@ -0,0 +1,17 @@
+package foo
+
+fun box(): String {
+    var l1: Long = 0x12344478935690
+    var l2: Long = 0x12344478935698
+    var diff: Long = l2 - l1
+    l1 += (diff / 2)
+    l2 -= (diff / 2)
+
+    assertEquals(l1, l2, "When L1 == L2")
+    assertEquals(l1.hashCode(), l2.hashCode(), "L1.hashCode() == L2.hashCode()")
+
+    var l3: Any = l2
+    assertEquals(l1.hashCode(), l3.hashCode(), "Any(Long).hashCode()")
+
+    return "OK"
+}