Fix that alows local symbols to be used as parameters to non-global template functions reverted

[Timon Gehr]

A heads-up for those of you who have started to rely on this fix in DMD:
https://github.com/dlang/dmd/pull/9702
https://issues.dlang.org/show_bug.cgi?id=5710

A workaround is to use static template functions with UFCS instead of 
member template functions. (Without this fix, any member template 
function with an alias parameter is a code smell.)