JS: move more test to box tests

js/js.translator/testData/box/standardClasses/mutableMapRemoveWithCollision.kt

@@ -0,0 +1,22 @@
+package foo
+
+class A {
+    override fun hashCode() = 23456
+}
+
+fun box(): String {
+    val x = A()
+    val y = A()
+
+    val map = mutableMapOf<A, Int>()
+    map[x] = 1
+    assertEquals(1, map.size)
+
+    map.remove(y)
+    assertEquals(1, map.size)
+
+    map.remove(x)
+    assertEquals(0, map.size)
+
+    return "OK"
+}