1. ConstantValue
* just holds some value and its type
* implementations for concrete constants
2. CompileTimeConstant
* is only produced by ConstantExpressionEvaluator
* has additional flags (canBeUsedInAnnotation etc)
* has two implementations TypedCompileTimeConstant containing a constant value
and IntegerValueConstant which does not have exact type
* can be converted to ConstantValue
Adjustt usages to use ConstantValue if flags are not needed
Add tests for some uncovered cases
Add a file in package 'kotlin.jvm.functions' to the project and replace
explicit imports of functions 'kotlin.Function{n}' to two imports 'kotlin.*'
and 'kotlin.jvm.functions.*', so that the codebase can be compiled both by the
old and by the new compiler
Introduce DeclarationDescriptor.builtIns extension to get builtins where descriptors are available
Introduce various utilities in KotlinBuiltIns to check for primitive types and get fq names of builtins