Adjust testData to new labels syntax

compiler/testData/diagnostics/tests/smartCasts/loops/assignWhenInsideWhileTrue.kt

@@ -1,6 +1,6 @@
 public fun foo(x: String?): Int {
     var y: Any
-    @loop while (true) {
+    loop@ while (true) {
         y = when (x) {
             null -> break@loop
             "abc" -> return 0

compiler/testData/diagnostics/tests/smartCasts/loops/nestedDoWhileWithLongContinue.kt

@@ -1,7 +1,7 @@
 fun x(): Boolean { return true }
 
 public fun foo(p: String?, r: String?): Int {
-    @outer do {
+    outer@ do {
         do {
             p!!.length()
             if (!x()) continue@outer

compiler/testData/diagnostics/tests/smartCasts/loops/nestedLoopsWithLongBreak.kt

@@ -3,7 +3,7 @@ fun x(p: String): Boolean { return p == "abc" }
 public fun foo(p: String?, r: String?, q: String?): Int {
     while(true) {
         q!!.length()
-        @loop do {
+        loop@ do {
             while(true) {
                 p!!.length()
                 if (x(<!DEBUG_INFO_SMARTCAST!>p<!>)) break@loop

compiler/testData/diagnostics/tests/smartCasts/loops/nestedLoopsWithLongContinue.kt

@@ -1,7 +1,7 @@
 fun x(): Boolean { return true }
 
 public fun foo(p: String?, r: String?, q: String?): Int {
-    @outer while(true) {
+    outer@ while(true) {
         q!!.length()
         do {
             if (x()) continue@outer

compiler/testData/diagnostics/tests/smartCasts/loops/plusAssignWhenInsideDoWhile.kt

@@ -3,7 +3,7 @@ fun bar(): Boolean { return true }
 public fun foo(x: String?): Int {
     var y: Int?
     y = 0
-    @loop do {
+    loop@ do {
         <!DEBUG_INFO_SMARTCAST!>y<!> += when (x) {
             null -> break@loop
             "abc" -> return 0

compiler/testData/diagnostics/tests/smartCasts/loops/whenInsideWhileTrue.kt

@@ -1,5 +1,5 @@
 public fun foo(x: String?): Int {
-    @loop while (true) {
+    loop@ while (true) {
         when (x) {
             null -> break@loop
             "abc" -> return 0

compiler/testData/diagnostics/tests/smartCasts/loops/whenReturnInsideWhileTrue.kt

@@ -1,5 +1,5 @@
 public fun foo(x: String?): Int {
-    @loop while (true) {
+    loop@ while (true) {
         when (x) {
             null -> return -1
             "abc" -> return 0