[FE] Substitute fixed type variables with inferred stub types

Actually, a type variable might be fixed into a stub type. Such stub type should be substituted before sub calls completion

^KT-51988 Fixed

compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/ConstraintSystemBuilder.kt

@@ -18,6 +18,7 @@ interface ConstraintSystemOperation {
     fun markCouldBeResolvedWithUnrestrictedBuilderInference()
     fun unmarkPostponedVariable(variable: TypeVariableMarker)
     fun removePostponedVariables()
+    fun substituteFixedVariables(substitutor: TypeSubstitutorMarker)
 
     fun getBuiltFunctionalExpectedTypeForPostponedArgument(
         topLevelVariable: TypeConstructorMarker,

compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/model/NewConstraintSystemImpl.kt

@@ -144,6 +144,10 @@ class NewConstraintSystemImpl(
         storage.postponedTypeVariables.clear()
     }
 
+    override fun substituteFixedVariables(substitutor: TypeSubstitutorMarker) {
+        storage.fixedTypeVariables.replaceAll { _, type -> substitutor.safeSubstitute(type) }
+    }
+
     override fun putBuiltFunctionalExpectedTypeForPostponedArgument(
         topLevelVariable: TypeConstructorMarker,
         pathToExpectedType: List<Pair<TypeConstructorMarker, Int>>,