Parameters not accessing uninitiated parsed functions array

`ReflectionBase::$parsedFunctions` was not being populated from `ParserResult::$functions`.

[Closes #423]
[Closes #437]
@Mikulas Thanks for the patch :+1: . I have reported issue #440 and later on came to know this patch fixed that issue. @TomasVotruba be soon to fix this up as we are culpri to use `v2.8.1` and can't shift to `apigen-4.0.0-RC4.phar` version because of this error as we use functions that support `@parameters` mostly. Hope you will look this patch and merge soon :)