Extremely conservative escape analysis. (#212)

backend.native/tests/runtime/memory/escape0.kt

@@ -0,0 +1,58 @@
+fun foo1(arg: String) : String = arg
+
+/*
+fun foo2(arg: String) : String = arg + " foo2"
+
+fun bar(arg1: String, arg2: String) : String  = arg1 + " bar " + arg2
+
+fun zoo1() : String {
+    var x = foo1("")
+    var y = 4
+    return x
+}
+
+fun zoo2() : String {
+    val x = foo1("")
+    var y = 5
+    return x
+}
+
+class Node(var previous: Node?)
+
+fun zoo3() : Node {
+    var current = Node(null)
+    for (i in 1 .. 5) {
+        current = Node(current)
+    }
+    return current
+}
+
+fun zoo4(arg: Int) : Any {
+    var a = Any()
+    var b = Any()
+    var c = Any()
+    a = b
+    val x = 3
+    a = when {
+        x < arg -> b
+        else -> c
+    }
+    return a
+} */
+
+fun zoo5(arg: String) : String {
+    return arg + foo1(arg)
+}
+
+fun zoo6(arg: Any) : Any {
+    return zoo7(arg, "foo", 11)
+}
+
+fun zoo7(arg1: Any, arg2: Any, selector: Int) : Any {
+    return if (selector < 2) arg1 else arg2;
+}
+
+fun main(args : Array<String>) {
+    val z = zoo7(Any(), Any(), 1)
+    //println(bar(foo1(foo2("")), foo2(foo1(""))))
+}