maint: Remove unneeded input validation from internal fcns in private/ directories. * scripts/general/private/__isequal__.m, scripts/general/private/__splinen__.m, scripts/image/private/__imwrite__.m, scripts/image/private/ind2x.m, scripts/miscellaneous/private/__xzip__.m, scripts/miscellaneous/private/display_info_file.m, scripts/pkg/private/describe.m, scripts/pkg/private/get_forge_pkg.m, scripts/pkg/private/unload_packages.m, scripts/plot/private/__actual_axis_position__.m, scripts/plot/private/__add_datasource__.m, scripts/plot/private/__clabel__.m, scripts/plot/private/__errcomm__.m, scripts/plot/private/__errplot__.m, scripts/plot/private/__fltk_print__.m, scripts/plot/private/__gnuplot_get_var__.m, scripts/plot/private/__go_draw_axes__.m, scripts/plot/private/__go_draw_figure__.m, scripts/plot/private/__interp_cube__.m, scripts/plot/private/__line__.m, scripts/plot/private/__next_line_color__.m, scripts/plot/private/__next_line_style__.m, scripts/plot/private/__plt__.m, scripts/plot/private/__pltopt__.m, scripts/signal/private/rectangle_lw.m, scripts/signal/private/rectangle_sw.m, scripts/signal/private/triangle_lw.m, scripts/signal/private/triangle_sw.m, scripts/sparse/private/__sprand_impl__.m, scripts/statistics/models/private/logistic_regression_derivatives.m, scripts/statistics/models/private/logistic_regression_likelihood.m: Remove unneeded input validation from internal fcns in private/ directories.

syntax: regexp
# The recurrent (^|/) idiom in the regexps below should be understood
# to mean "at any directory" while the ^ idiom means "from the
# project's top-level directory".

# gnulib makes these silly backup files
.~$

# This directory gets created by gnulib during the build. 
# It contains no Octave files.
^libgnu/*

# This directory mostly contains cruft during build time, but it does
# contain some Octave code, so we gotta be a bit more careful about
# what we ignore here
^m4/(?!ax_).+\.m4$

# Emacs tools create these
(^|/)TAGS$
(^|/)semantic.cache$

(/|^)Makefile\.in$
^INSTALL$

^aclocal\.m4$
^build-.*($|/)
^configure$
^autom4te\.cache($|/)
^config\.in\.h$

# e.g. doc/faq/OctaveFAQ.info
#      doc/interpreter/octave.info-4
^doc/.*\.info(-\d)?$

^doc/\w*/stamp-vti$
^doc/\w*/version\.texi$
^doc/interpreter/images\.mk$

# e.g. liboctave/operators/smx-op-inc.mk
^liboctave/operators/\w+-op-\w+\.mk$

^libinterp/dldfcn/module\.mk$