Fix display of "const" methods in wxGTK assert dialog.

Fix display of "const" methods in wxGTK assert dialog.

Don't separate the function name and its arguments types in 2 different
columns in the assert dialog, this doesn't really work with const methods as
"const" can't be separated from the function like this. The old code just
didn't take "const" into account at all and mangled all the const methods by
showing ") cons" (no typo) at the end.

Just show everything in one column to avoid the problem and also simplify the
code.

Closes #14104.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70954 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775