[FIR2IR] Introduce staged transformation (first step)

Now FE IR -> BE IR transformation is performed in multiple stages
controller by Fir2IrConverter. Stages are
 * files & classes registration
 * supertypes & type parameters handling
 * functions & properties signature generation
 * body generation

After each step we have guarantee (with exception of local classes &
type inference combination, and external symbols) that required symbols
(class/function/property/variable/type parameter)
are already bound to real declarations and have correct parents.

This commit also fixes incorrect parents for local classes

compiler/testData/codegen/box/closures/captureExtensionReceiverX2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun String.f(x: String): String {
     fun String.g() = { this@f + this@g }()
     return x.g()

compiler/testData/codegen/box/closures/captureInSuperConstructorCall/localFunctionCapturedInLambda.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 open class Base(val fn: () -> String)
 
 fun box(): String {

compiler/testData/codegen/box/closures/captureOuterProperty/kt4176.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 open class Z(val s: Int) {
     open fun a() {}
 }

compiler/testData/codegen/box/closures/capturedLocalGenericFun.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box() : String {
 
     fun <T> local(s : T) : T {

compiler/testData/codegen/box/closures/closureInsideClosure/localFunInsideLocalFun.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     fun rec(n : Int) {
         fun x(m : Int) {

compiler/testData/codegen/box/closures/closureInsideClosure/localFunInsideLocalFunDifferentSignatures.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     fun rec(n : Int) {
         fun x(m : Int, k : Int) {

compiler/testData/codegen/box/closures/closureInsideClosure/threeLevels.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     fun foo(x: Int) {
         fun bar(y: Int) {

compiler/testData/codegen/box/closures/closureInsideClosure/threeLevelsDifferentSignatures.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     fun foo(x: Int, s: String): String {
         fun bar(y: Int) {

compiler/testData/codegen/box/closures/closureInsideClosure/varAsFunInsideLocalFun.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 //KT-3276
 
 fun box(): String {

compiler/testData/codegen/box/closures/kt3905.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box() : String {
     fun <T> foo(t:() -> T) : T = t()
 

compiler/testData/codegen/box/closures/kt5589.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val x = "OK"
     fun bar(y: String = x): String = y

compiler/testData/codegen/box/closures/localClassFunClosure.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val o = "O"
     fun ok() = o + "K"

compiler/testData/codegen/box/closures/localFunctionInFunction.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
 
   fun local():Int {

compiler/testData/codegen/box/closures/localFunctionInInitializer.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
 
   fun local():Int {

compiler/testData/codegen/box/closures/localGenericFun.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box() : String {
 
     fun <T> local(s : T) : T {

compiler/testData/codegen/box/closures/recursiveClosure.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun foo(s: String): String {
     fun bar(count: Int): String =
         if (count == 0) s else bar(count - 1)