Revert "Fix rendering of BibLaTeX ISO 690 in TeX Live <=2017"

This reverts commit a4092f80.

example/mu/example.dtx

@@ -478,42 +478,6 @@
 \counterwithout{table}{chapter}  % Flat numbering of tables.
 \counterwithout{figure}{chapter} % Flat numbering of figures.
 %</econ>
-%% The following code fixes the rendering of BibLaTeX ISO 690
-%% references in old TeX Live (such as the one at Overleaf).
-\thesisload
-\makeatletter
-\def\thesis@biblatexiso@fix@package{iso-numeric.bbx}
-\def\thesis@biblatexiso@fix@end{\relax}
-\newif\ifthesis@biblatexiso@fix@
-\thesis@biblatexiso@fix@false
-\def\thesis@biblatexiso@fix@next#1,{%
-  \def\thesis@biblatexiso@fix@current{#1}%
-  \ifx\thesis@biblatexiso@fix@current\thesis@biblatexiso@fix@package
-    \thesis@biblatexiso@fix@true
-  \fi
-  \ifx\thesis@biblatexiso@fix@current\thesis@biblatexiso@fix@end
-    \expandafter
-    \@gobble
-  \fi
-  \thesis@biblatexiso@fix@next
-}
-\expandafter\expandafter\expandafter\thesis@biblatexiso@fix@next\@filelist,\relax,
-\ifthesis@biblatexiso@fix@
-  \defbibenvironment{bibliography}
-    {\list%
-       {\MethodFormat}%
-       {\setlength{\labelwidth}{\labelnumberwidth}%
-        \setlength{\leftmargin}{\labelwidth}%
-        \setlength{\labelsep}{\biblabelsep}%
-        \addtolength{\leftmargin}{\labelsep}%
-        \setlength{\itemsep}{\bibitemsep}%
-        \setlength{\parsep}{\bibparsep}}%
-        \renewcommand*{\makelabel}[1]{\hss##1}
-        }%
-    {\endlist}%
-  {\item}%
-\fi
-\makeatother
 \begin{document}
 %<*econ>
 \makeatletter