K2: repeat K1 representation for flexible type parameters

This commit changes the behavior of KT-59138 effectively declining it in 2.0.
However, we plan to implement KT-59138 behavior under a feature
flag in 2.0 (see KT-66447), and switch this feature on version 2.x.

Also, this commit implements the LC resolution about postponing
KT-57014 change. We don't have KT-57014 described behavior in 2.0 anymore.
However, we plan to implement a deprecation warning here, see KT-65578.

After this commit, 6 diagnostic tests become incorrectly broken:
- 5 tests from PurelyImplementedCollection group
- a test platformTypes/nullableTypeArgument.kt

This commit also breaks currently fixed-in-k2 KT-50134
(it is fixed again in the following commits),
as well as KT-58933 (it will remain not fixed till we enable KT-59138
behavior again).

#KT-65596 In Progress
#KT-57014 In Progress
#KT-58933 Submitted

analysis/analysis-api/testData/components/callResolver/resolveCall/samConstructorCall.txt

@@ -7,13 +7,13 @@ KtSuccessCallInfo:
       signature = KtFunctionLikeSignature:
         receiverType = null
         returnType = java.util.Comparator<kotlin.Int!>
-        symbol = kotlin/Comparator(function: kotlin.Function2<ft<T & Any, T?>, ft<T & Any, T?>, kotlin.Int>): java.util.Comparator<T>
+        symbol = kotlin/Comparator(function: kotlin.Function2<T!, T!, kotlin.Int>): java.util.Comparator<T>
         valueParameters = [
           KtVariableLikeSignature:
             name = function
             receiverType = null
             returnType = kotlin.Function2<kotlin.Int!, kotlin.Int!, kotlin.Int>
-            symbol = function: kotlin.Function2<ft<T & Any, T?>, ft<T & Any, T?>, kotlin.Int>
+            symbol = function: kotlin.Function2<T!, T!, kotlin.Int>
             callableIdIfNonLocal = null
         ]
         callableIdIfNonLocal = kotlin/Comparator
@@ -25,6 +25,6 @@ KtSuccessCallInfo:
         name = function
         receiverType = null
         returnType = kotlin.Function2<kotlin.Int!, kotlin.Int!, kotlin.Int>
-        symbol = function: kotlin.Function2<ft<T & Any, T?>, ft<T & Any, T?>, kotlin.Int>
+        symbol = function: kotlin.Function2<T!, T!, kotlin.Int>
         callableIdIfNonLocal = null)
     }