[Ptach, fortran] PR25818 - Problem with handling optional and entry master arguments

[Paul Thomas]

Steve,
> Bootstrap and regression tested on i386-*-freebsd.
>   
I put the test for f->sym at the start of the loop block, just to be 
minutely more effecient :-)

The combination of this and pr30084 is regtesting right now.  I trust 
that it's OK to commit to trunk, when it's done?

Thanks

Paul