StringTable::insert should return NULL if key already exists
fix Issue 13668 - [ICE] unable to compile __traits(allMembers...)
fix Issue 10528 - Private constant (enum) properties not private
[Refactoring] fix code style in ctfe interpreter
Merge pull request #4105 from 9rnsr/refactor_ctfe

[Refactoring] fix code style in ctfe interpreter
Merge pull request #4102 from MartinNowak/fixStringTableInsert

StringTable::insert should return NULL if key already exists
Merge pull request #4104 from 9rnsr/fix10528

Issue 10528 - Private constant (enum) properties not private
Merge pull request #4103 from 9rnsr/fix13668

Issue 13668 - [ICE] unable to compile __traits(allMembers...)