Fix DeserializerForDecompiler: create package fragment provider for missing dependencies

idea/testData/libraries/decompiledText/DependencyOnNestedClasses.expected.kt

@@ -0,0 +1,8 @@
+// IntelliJ API Decompiler stub source generated from a class file
+// Implementation of methods is not available
+
+package test
+
+public final class DependencyOnNestedClasses() : dependency.D.Nested {
+    internal final fun f(nc: dependency.D.NestedInClassObject, i: dependency.D.Inner, ii: dependency.D.Inner.Inner, nn: dependency.D.Nested.Nested): dependency.D.Nested { /* compiled code */ }
+}