remove the now unused show test util function

tests/test_functions/show.fish

@@ -1,18 +0,0 @@
-# Show information about the named var(s) passed to us.
-function show --no-scope-shadowing
-    for _v in $argv
-        if set -q $_v
-            set -l _c (count $$_v)
-            printf '$%s count=%d\n' $_v $_c
-            # This test is to work around a bogosity of the BSD `seq` command. If called with
-            # `seq 0` it emits `1`, `0`. Whereas that GNU version outputs nothing.
-            if test $_c -gt 0
-                for i in (seq $_c)
-                    printf '$%s[%d]=|%s|\n' $_v $i $$_v[1][$i]
-                end
-            end
-        else
-            echo \$$_v is not set
-        end
-    end
-end