TO SPLIT: Implement IDE modules
Introduce MultiModuleHighlightingTest

Checks that analysis produces expected diagnostics when configured by real IDEA module
Remove additional logic for comparing files in JavaClassFinderImpl
ResolveSessionForBodies is not ModificationTracker
JDR: Drop additional check for builtins

Not needed since module are configured correctly
JDR: remove some random logic, see what happens
JDR: some other random code deleted, what happen's?
extractFunctionForDebuggerUtil.kt
PluginDeclarationProviderFactoryService.kt
TODOS
InternalMode