Clean size/length/first/head/empty properties and functions.

libraries/stdlib/test/TuplesTest.kt

@@ -40,8 +40,8 @@ class PairTest {
     }
 
     test fun pairHashSet() {
-        val s = hashSet(Pair(1, "a"), Pair(1, "b"), Pair(1, "a"))
-        assertEquals(2, s.size)
+        val s = hashSetOf(Pair(1, "a"), Pair(1, "b"), Pair(1, "a"))
+        assertEquals(2, s.size())
         assertTrue(s.contains(p))
     }
 }
@@ -85,8 +85,8 @@ class TripleTest {
     }
 
     test fun tripleHashSet() {
-        val s = hashSet(Triple(1, "a", 0.07), Triple(1, "b", 0.07), Triple(1, "a", 0.07))
-        assertEquals(2, s.size)
+        val s = hashSetOf(Triple(1, "a", 0.07), Triple(1, "b", 0.07), Triple(1, "a", 0.07))
+        assertEquals(2, s.size())
         assertTrue(s.contains(t))
     }
 }