Increase memory for 'All * Tests' configurations

Use the same parameters as for All Tests
Make CharSequence.length a function instead of property

And String.length as well.

This is done for JVM interoperability: java.lang.CharSequence is an open class
and has a function 'length()' which should be implemented in subclasses
somehow.

A minor unexpected effect of this is that String.length() is now a compile-time
constant (it wasn't such as a property because properties are not supported in
compile-time constant evaluation)

 #KT-3571 Fixed
Rename CharSequence.get to charAt

This is done for JVM interoperability. There's still a member function
String.get() and an extension function "get" on CharSequence

 #KT-1730 Fixed
 #KT-5389 Fixed
Add CharSequence.subSequence

This is done primarily for JVM interoperability, otherwise it's impossible to
inherit from CharSequence there. On JS subSequence at the moment just invokes
substring.

 #KT-5956 Fixed
Rename BaseDescriptorLoader before conversion
Convert BaseDescriptorLoader to kotlin
Prettify code in BaseDescriptorLoader after conversion
Inline BaseDescriptorLoader#getPackagePartClassName utilities
Minor: simplify code
Make AnnotationLoader and ConstantLoader accept descriptor-independent data

Rewrite BaseDescriptorLoader to operate on data derived from proto
Intdoduce ProtoContainer to replace containing descriptor as input data
Rename AnnotationDescriptorLoader, ConstantDescriptorLoader and DescriptorLoadersStorage before conversion
Convert AnnotationDescriptorLoader, ConstantDescriptorLoader and DescriptorLoadersStorage
Prettify AnnotationDescriptorLoader, ConstantDescriptorLoader and DescriptorLoadersStorage after conversion
Merge AnnotationLoader and ConstantLoader into single interface

Merge all implementation classes into single BinaryClassAnnotationAndConstantLoader
Extract non-descriptor specific abstract ancestor for BinaryClassAnnotationAndConstantLoader
Fix calling toString() on ProtoContainer
Prettify code in BinaryClassAnnotationAndConstantLoaderImpl
Move check for special annotation to an abstract class
Replaced filterIsInstance with class-literal argument with simplified version
Extension PsiElement.getParentByType with reified T