Memory optimization: Do not retain LinkedHashSets in caches

LinkedHashSets are replaced with tight ArrayLists
Memory optimization: Fewer ConcurrentHashMap.Segment instances
Merge stored empty lists and sets to singe object
Memory optimization. Do not put sets into caches
Fixed accidental override of new method in IDEA API.
Gradle plugin: fix sourceSets for flavors (android)
 Fix for KT-6196: ClassCastException on unit property initializer

   #KT-6196 Fixed
Fix for KT-6202: Redundant and wrong linenumber after if/else condition

  #KT-6202 Fixed
Converting JetScope's implementations to Kotlin (in progress)
Converted method to property
Converted to Kotlin
Converted to Kotlin
Minor code simplifications using Kotlin
Converted WritableScope to Kotlin
Converted ChainedScope to Kotlin
Converted FilteringScope to Kotlin
Converted SubstitutingScope to Kotlin
Simplified code
Converted LazyImportScopy to Kotlin
Minor code simplifications