Move checkTypePosition to VarianceChecker in frontend

This is a partial revert of 279ff0b, which is no longer needed because
of the previous commit

core/descriptors/src/org/jetbrains/kotlin/types/VarianceChecker.kt

@@ -1,67 +0,0 @@
-/*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.kotlin.types
-
-import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
-import org.jetbrains.kotlin.types.checker.TypeCheckingProcedure
-import org.jetbrains.kotlin.types.checker.TypeCheckingProcedure.EnrichedProjectionKind
-import org.jetbrains.kotlin.utils.DO_NOTHING_3
-
-interface TypeHolder<out D : TypeHolder<D>> {
-    val type: KotlinType
-    val arguments: List<TypeHolderArgument<D>?>
-}
-
-interface TypeHolderArgument<out D : TypeHolder<D>> {
-    val projection: TypeProjection
-    val typeParameter: TypeParameterDescriptor?
-    val holder: D
-}
-
-fun <D : TypeHolder<D>> D.checkTypePosition(
-    position: Variance,
-    reportError: (TypeParameterDescriptor, D, Variance) -> Unit = DO_NOTHING_3,
-    customVariance: (TypeParameterDescriptor) -> Variance? = { null }
-): Boolean {
-    val classifierDescriptor = type.constructor.declarationDescriptor
-    if (classifierDescriptor is TypeParameterDescriptor) {
-        val declarationVariance = customVariance(classifierDescriptor) ?: classifierDescriptor.variance
-        if (!declarationVariance.allowsPosition(position)
-            && !type.annotations.hasAnnotation(org.jetbrains.kotlin.builtins.KotlinBuiltIns.FQ_NAMES.unsafeVariance)
-        ) {
-            reportError(classifierDescriptor, this, position)
-        }
-        return declarationVariance.allowsPosition(position)
-    }
-
-    var noError = true
-    for (argument in arguments) {
-        if (argument?.typeParameter == null || argument.projection.isStarProjection) continue
-
-        val projectionKind = TypeCheckingProcedure.getEffectiveProjectionKind(argument.typeParameter!!, argument.projection)!!
-        val newPosition = when (projectionKind) {
-            EnrichedProjectionKind.OUT -> position
-            EnrichedProjectionKind.IN -> position.opposite()
-            EnrichedProjectionKind.INV -> Variance.INVARIANT
-            EnrichedProjectionKind.STAR -> null // CONFLICTING_PROJECTION error was reported
-        }
-        if (newPosition != null) {
-            noError = noError and argument.holder.checkTypePosition(newPosition, reportError, customVariance)
-        }
-    }
-    return noError
-}