Don't use $ in package fragment class names

Package fragment classes now are named "*Package-<filename>-<hash>" instead of
"*Package$src$<filename>$<hash>". This will help to avoid erroneous code in
intellij FileManager, which assumes that classes with dollars are always inner
classes of some other class (see AnnotationDescriptorDeserializer)

compiler/testData/codegen/bytecodeText/topLevelFunWithDefaultArgs.kt

@@ -1,4 +1,4 @@
 fun foo(a: Int = 1) {}
 
 //0 _DefaultPackage.foo
-//3 INVOKESTATIC _DefaultPackage\$src\$
+//3 INVOKESTATIC _DefaultPackage-