Update test file to actually show the bug was fixed

required/graphics/testfiles/github-0519.luatex.tlg

@@ -0,0 +1,10 @@
+This is a generated file for the l3build validation system.
+Don't change this file in any respect.
+File: foob^^e1.eps.gz Graphic file (type eps)
+<foob^^e1.eps.gz>
+> \box...=
+\hbox(32.12+0.0)x36.135, direction TLT
+.\hbox(32.12+0.0)x36.135, direction TLT
+..\special{PSfile="foob^^e1.eps.gz" llx=44 lly=527 urx=80 ury=559 rwi=360 }
+! OK.
+l. ...\showbox0

required/graphics/testfiles/github-0519.tlg

@@ -1,8 +1,10 @@
 This is a generated file for the l3build validation system.
 Don't change this file in any respect.
-! TeX capacity exceeded, sorry [input stack size=5000].
-\Gin@ext ->\Gin@ext 
-                    .gz
-l. ...\sbox0{\includegraphics{fooba.eps.gz}}
-If you really absolutely need more capacity,
-you can ask a wizard to enlarge me.
+File: foob^^c3^^a1.eps.gz Graphic file (type eps)
+<foob^^c3^^a1.eps.gz>
+> \box...=
+\hbox(32.12+0.0)x36.135
+.\hbox(32.12+0.0)x36.135
+..\special{PSfile="foob^^c3^^a1.eps.gz" llx=44 lly=527 urx=80 ury=559 rwi=360 }
+! OK.
+l. ...\showbox0