Don't lookup built-in classes by invalid names

 #KT-5869 Fixed
Support static method references

 #KT-5123 Fixed
Internal visibility works the same as public

Fix test data
This change is needed to preserve old behaviour for M9
isFriend() utilities become unused after this change
JS backend: original long.js from closure-library
JS backend: prepare long.js for use in translator
JS backend: add support for Long type
JS backend: tests for Long type support
JS backend: support for char type
JS backend: tests for char type