Add more tests in uncommonCases folder

1) dataClass.kt - test with data class
2) receiver.kt - test with Int extension receiver
3) delegation.kt - test with implementation by delegation

compiler/visualizer/testData/uncommonCases/testFiles/dataClass.kt

@@ -0,0 +1,14 @@
+data class Vector(val x: Int, val y: Int) {
+    fun plus(other: Vector): Vector = Vector(x + other.x, y + other.y)
+}
+
+fun main() {
+    val a = Vector(1, 2)
+    val b = Vector(-1, 10)
+
+    println("a = $a, b = ${b.toString()}")
+    println("a + b = " + (a + b))
+    println("a hash - ${a.hashCode()}")
+
+    println("a is equal to b ${a.equals(b)}")
+}