FIR tower resolve: add level with implicit extension receiver

compiler/fir/resolve/testData/resolve/extension.txt

@@ -2,5 +2,5 @@ FILE: extension.kt
     public final fun R|kotlin/String|.foo(): R|kotlin/Unit| {
     }
     public final fun R|kotlin/String|.bar(): R|kotlin/Unit| {
-        <Unresolved name: foo>#()
+        R|/foo|()
     }

compiler/fir/resolve/testData/resolve/stdlib/arrayFirstOrNull.txt

@@ -9,7 +9,7 @@ FILE: arrayFirstOrNull.kt
     }
     public final fun <T> R|kotlin/Array<out T>|.firstOrNullX(): R|T|? {
         ^firstOrNullX when () {
-            <Unresolved name: isEmpty>#() ->  {
+            <Ambiguity: isEmpty, [kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/collections/isEmpty, kotlin/text/isEmpty]>#() ->  {
                 Null(null)
             }
             else ->  {

compiler/fir/resolve/testData/resolve/stdlib/topLevelResolve.txt

@@ -36,7 +36,7 @@ FILE: topLevelResolve.kt
         }
         )
         lval viaWith: R|kotlin/Nothing| = R|kotlin/with|<R|kotlin/collections/List<kotlin/Int>|, R|kotlin/Nothing|>(R|kotlin/collections/listOf|<R|kotlin/Int|>(Int(42)), <L> = with@fun R|kotlin/collections/List<kotlin/Int>|.<anonymous>(it: R|kotlin/collections/List<kotlin/Int>|): R|kotlin/Function2<kotlin/collections/List<kotlin/Int>, kotlin/collections/List<kotlin/Int>, kotlin/Nothing>| {
-            <Unresolved name: map>#(<L> = map@fun <implicit>.<anonymous>(): <implicit> {
+            <Ambiguity: map, [kotlin/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/collections/map, kotlin/sequences/map, kotlin/text/map]>#(<L> = map@fun <implicit>.<anonymous>(): <implicit> {
                 it#.times#(it#)
             }
             )
@@ -49,7 +49,7 @@ FILE: topLevelResolve.kt
         }
         )
         lval indices: R|kotlin/Nothing| = R|kotlin/with|<R|kotlin/String|, R|kotlin/Nothing|>(String(), <L> = with@fun R|kotlin/String|.<anonymous>(it: R|kotlin/String|): R|kotlin/Function2<kotlin/String, kotlin/String, kotlin/Nothing>| {
-            <Unresolved name: indices>#
+            <Ambiguity: indices, [kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/collections/indices, kotlin/text/indices]>#
         }
         )
         lval indicesNoWith: R|kotlin/ranges/IntRange| = String().R|kotlin/text/indices|