JvmName annotation support, single-file facade case (just rename file facade class)

- initial implementation of JvmFileClassesProvider
- migrate some of PackagePartClassUtil usages to JvmFileClassesProvider (mostly in Codegen)
- placeholder ("no resolve") implementation for migration period and unclear cases
- tests

compiler/testData/codegen/boxWithJava/fileClasses/differentFiles/Baz.java

@@ -0,0 +1,5 @@
+public class Baz {
+    public static String baz() {
+        return Foo.foo() + Bar.bar();
+    }
+}