JVM IR: fix flags of $default methods in multi-file facades

Do not change origin of multifile class bridges to something else
because, as it turns out, there are numerous origin-specific checks in
the codegen that start to behave differently for multifile bridges.
Instead of the method-targeted origin MULTIFILE_BRIDGE, use new class
origin JVM_MULTIFILE_CLASS to detect whether a declaration is a
multifile bridge.

 #KT-40198 Fixed
 #KT-43145 Fixed

compiler/testData/codegen/bytecodeListing/defaultArguments/functionInMultifileClass.kt

@@ -0,0 +1,24 @@
+// WITH_RUNTIME
+// The difference of JVM and JVM_IR in generating privateFunction here is reported at KT-41841.
+// FILE: test.kt
+
+@file:JvmMultifileClass
+@file:JvmName("A")
+
+private fun private(x: String = "") {}
+
+private inline fun privateInline(x: String, y: Int = 0) {}
+
+internal fun internal(x: String = "") {}
+
+internal inline fun internalInline(x: String, y: Int = 0) {}
+
+@PublishedApi
+internal fun published(x: String = "") {}
+
+@PublishedApi
+internal fun publishedInline(x: String = "") {}
+
+public fun public(x: String = "") {}
+
+public inline fun publicInline(x: String, y: Int = 0) {}