Do not query MultifileClassCodegen#classBuilder early on: this causes the class
file for the facade to be prematurely dumped to the disk in some cases, when
that class file is not yet completely generated. Instead fork the logic in
PropertyCodegen#generateSyntheticMethodIfNeeded: save metadata in parts,
generate method in the facade
For now, JVM and JS backends produce different metadata for package facades (and package parts),
and thus different output is expected for JVM and JS decompiler.
Split decompiler tests into common (decompiledText), JVM-specific (decompiledTextJvm),
and JS-specific (decompiledTextJs)
Join them back together if JS backend migrates to JVM-like package model.
Alexander Udalov