JVM IR: fix containing declaration for top level members in wrapped descriptors

In addition to fixing getContainingDeclaration, change origin of
multifile facades to FILE_CLASS since the corresponding class descriptor
should also be skipped when computing containing declaration. This fixes
the problem with internal function calls in -Xmultifile-parts-inherit
mode (previously we incorrectly mangled the function name in
MethodSignatureMapper), and also fixes coroutine intrinsic calls when
compiling kotlin-stdlib with JVM IR. In the latter case, all intrinsics
(such as isBuiltInSuspendCoroutineUninterceptedOrReturn) are present in
sources, and were previously not detected as intrinsics by the code in
`generateInlineIntrinsic` because the FQ name didn't match: it had an
additional component for the file class name.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/WrappedDescriptors.kt

@@ -12,7 +12,6 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.descriptors.impl.TypeAliasConstructorDescriptor
 import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.descriptors.IrBasedDeclarationDescriptor
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.types.classifierOrFail
 import org.jetbrains.kotlin.ir.types.toKotlinType
@@ -1056,11 +1055,12 @@ open class WrappedFieldDescriptor(
 
 private fun getContainingDeclaration(declaration: IrDeclarationWithName): DeclarationDescriptor {
     val parent = declaration.parent
-    return if (parent is IrClass && parent.origin == IrDeclarationOrigin.FILE_CLASS && parent.parent is IrExternalPackageFragment) {
-        // JVM IR adds facade classes for IR of functions/properties loaded from dependencies. However, these shouldn't exist
-        // in the descriptor hierarchy, since this is what the old backend (dealing with descriptors) expects.
-        return (parent.parent as IrExternalPackageFragment).packageFragmentDescriptor
+    val parentDescriptor = (parent as IrSymbolOwner).symbol.descriptor
+    return if (parent is IrClass && parent.origin == IrDeclarationOrigin.FILE_CLASS) {
+        // JVM IR adds facade classes for IR of functions/properties loaded both from sources and dependencies. However, these shouldn't
+        // exist in the descriptor hierarchy, since this is what the old backend (dealing with descriptors) expects.
+        parentDescriptor.containingDeclaration!!
     } else {
-        (parent as IrSymbolOwner).symbol.descriptor
+        parentDescriptor
     }
 }