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/testData/codegen/box/multifileClasses/optimized/internalFunction.kt

@@ -0,0 +1,19 @@
+// TARGET_BACKEND: JVM
+// IGNORE_LIGHT_ANALYSIS
+// WITH_RUNTIME
+// !INHERIT_MULTIFILE_PARTS
+
+// FILE: test.kt
+
+@file:JvmMultifileClass
+@file:JvmName("Test")
+
+internal fun <T> List<T>.first(): T = get(0)
+
+fun test(): String {
+    return listOf("OK").first()
+}
+
+// FILE: box.kt
+
+fun box(): String = test()