Backend support for function expression

compiler/testData/codegen/box/functions/functionLiteralExpression.kt

@@ -0,0 +1,25 @@
+fun Any.foo1() : ()-> String {
+  return { "239" + this }
+}
+
+fun Int.foo2() : (i : Int) -> Int {
+  return { x -> x + this }
+}
+
+fun fooT1<T>(t : T) = { t.toString() }
+
+fun fooT2<T>(t: T) = { (x:T) -> t.toString() + x.toString() }
+
+fun box() : String {
+  if( (10.foo1())() != "23910") return "foo1 fail"
+  if( (10.foo2())(1) != 11 ) return "foo2 fail"
+
+  if(1.{Int.() -> this + 1}() != 2) return "test 3 failed";
+  if(  {1}() != 1)  return "test 4 failed";
+  if(  {(x : Int) -> x}(1) != 1)  return "test 5 failed";
+  if(  1.{Int.(x : Int) -> x + this}(1) != 2) return "test 6 failed";
+  if(  1.({Int.() -> this})() != 1)  return "test 7 failed";
+  if(  (fooT1<String>("mama"))() != "mama")  return "test 8 failed";
+  if(  (fooT2<String>("mama"))("papa") != "mamapapa")  return "test 9 failed";
+  return "OK"
+}