[descriptors] Move DeclarationDescriptor#findPackage helper to core

There is nothing serialization-specific about this function

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/LegacyDescriptorUtils.kt

@@ -24,10 +24,8 @@ internal val DeclarationDescriptor.isExpectMember: Boolean
 internal val DeclarationDescriptor.isSerializableExpectClass: Boolean
     get() = this is ClassDescriptor && OptionalAnnotationUtil.shouldGenerateExpectClass(this)
 
-tailrec fun DeclarationDescriptor.findPackage(): PackageFragmentDescriptor {
+@Deprecated("Moved to the ':core:descriptors' module", level = DeprecationLevel.HIDDEN)
-    return if (this is PackageFragmentDescriptor) this
+fun DeclarationDescriptor.findPackage(): PackageFragmentDescriptor = findPackage()
-    else this.containingDeclaration!!.findPackage()
-}
 
 private fun sourceByIndex(descriptor: CallableMemberDescriptor, index: Int): SourceFile {
     val fragment = descriptor.findPackage() as KlibMetadataDeserializedPackageFragment

core/descriptors/src/org/jetbrains/kotlin/descriptors/descriptorUtil.kt

@@ -106,3 +106,8 @@ fun FunctionDescriptor.isTypedEqualsInValueClass(): Boolean {
 fun FunctionDescriptor.overridesEqualsFromAny(): Boolean = name == OperatorNameConventions.EQUALS
         && valueParameters.size == 1 && valueParameters[0].type.isNullableAny()
         && contextReceiverParameters.isEmpty() && extensionReceiverParameter == null
+
+tailrec fun DeclarationDescriptor.findPackage(): PackageFragmentDescriptor {
+    return if (this is PackageFragmentDescriptor) this
+    else this.containingDeclaration!!.findPackage()
+}

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/BuiltInFictitiousFunctionIrClassFactory.kt

@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.backend.konan
 
-import org.jetbrains.kotlin.backend.konan.descriptors.findPackage
 import org.jetbrains.kotlin.builtins.FunctionInterfacePackageFragment
 import org.jetbrains.kotlin.builtins.functions.FunctionClassDescriptor
 import org.jetbrains.kotlin.builtins.functions.FunctionTypeKind

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/InlineClasses.kt

@@ -6,7 +6,7 @@
 package org.jetbrains.kotlin.backend.konan
 
 import org.jetbrains.kotlin.utils.atMostOne
-import org.jetbrains.kotlin.backend.konan.descriptors.findPackage
+import org.jetbrains.kotlin.descriptors.findPackage
 import org.jetbrains.kotlin.backend.konan.ir.getSuperClassNotAny
 import org.jetbrains.kotlin.builtins.PrimitiveType
 import org.jetbrains.kotlin.descriptors.ClassDescriptor

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/ObjCInterop.kt

@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.backend.konan
 
-import org.jetbrains.kotlin.backend.konan.descriptors.findPackage
 import org.jetbrains.kotlin.backend.konan.descriptors.getAnnotationStringValue
 import org.jetbrains.kotlin.backend.konan.descriptors.getAnnotationValueOrNull
 import org.jetbrains.kotlin.backend.konan.descriptors.getStringValue

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/descriptors/LegacyDescriptorUtils.kt

@@ -81,11 +81,6 @@ fun ClassDescriptor.isAbstract() = this.modality == Modality.SEALED || this.moda
 internal val FunctionDescriptor.target: FunctionDescriptor
     get() = (if (modality == Modality.ABSTRACT) this else resolveFakeOverride()).original
 
-tailrec internal fun DeclarationDescriptor.findPackage(): PackageFragmentDescriptor {
-    return if (this is PackageFragmentDescriptor) this
-    else this.containingDeclaration!!.findPackage()
-}
-
 internal fun DeclarationDescriptor.findPackageView(): PackageViewDescriptor {
     val packageFragment = this.findPackage()
     return packageFragment.module.getPackage(packageFragment.fqName)

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/serialization/KonanInteropModuleDeserializer.kt

@@ -9,12 +9,12 @@ import org.jetbrains.kotlin.backend.common.serialization.DescriptorByIdSignature
 import org.jetbrains.kotlin.backend.common.serialization.IrModuleDeserializer
 import org.jetbrains.kotlin.backend.common.serialization.IrModuleDeserializerKind
 import org.jetbrains.kotlin.backend.common.serialization.encodings.BinarySymbolData
-import org.jetbrains.kotlin.backend.konan.descriptors.findPackage
 import org.jetbrains.kotlin.backend.konan.descriptors.isInteropLibrary
 import org.jetbrains.kotlin.backend.konan.ir.interop.IrProviderForCEnumAndCStructStubs
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.descriptors.findPackage
 import org.jetbrains.kotlin.ir.IrBuiltIns
 import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.declarations.IrModuleFragment