[FIR] Never create ConeSubstitutorByMap with empty substitution

Relates to KT-66323

compiler/fir/checkers/checkers.jvm/src/org/jetbrains/kotlin/fir/analysis/jvm/checkers/expression/FirExpressionJavaNullabilityWarningCheckers.kt

@@ -80,7 +80,7 @@ object FirQualifiedAccessJavaNullabilityWarningChecker : FirQualifiedAccessExpre
             }
         }
 
-        return ConeSubstitutorByMap(substitutionMap, session)
+        return ConeSubstitutorByMap.create(substitutionMap, session)
     }
 }
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirCastDiagnosticsHelpers.kt

@@ -279,7 +279,7 @@ fun findStaticallyKnownSubtype(
 
     // At this point we have values for all type parameters of List
     // Let's make a type by substituting them: List<T> -> List<Foo>
-    val substitutor = ConeSubstitutorByMap(resultSubstitution, session)
+    val substitutor = ConeSubstitutorByMap.create(resultSubstitution, session)
     return substitutor.substituteOrSelf(subtypeWithVariablesType)
 }
 

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirInconsistentTypeParameterHelpers.kt

@@ -69,7 +69,7 @@ private fun buildDeepSubstitutionMultimap(
             for (index in 0 until count) {
                 val typeArgument = typeArguments[index]
 
-                val substitutedArgument = ConeSubstitutorByMap(substitution, session)
+                val substitutedArgument = ConeSubstitutorByMap.create(substitution, session)
                     .substituteArgument(typeArgument, index)
                     ?: typeArgument
                 val substitutedType = substitutedArgument.type ?: continue