ada: Remove special-case for parentheses in expansion for GNATprove

ada: Remove special-case for parentheses in expansion for GNATprove

When expanding of inequality operators for GNAT we were adding extra
parens, supposedly to "fix Sprint output" (source print); for GNATprove
we didn't, as these extra parens were leading to wrong columns for check
messages.

Adding these extra parens couldn't be a right, because Sprint should
produce reasonable output regardless of the parens, especially since we
don't care about parens when creating AST in expansion. Avoiding them
for GNATprove couldn't be right either, because source printing should
work regardless of the GNAT/GNATprove mode.

The proper fix for GNAT is rather to not add parens at all and tune
source printing, if necessary. The proper fix for GNATprove is not have
them either, as it confuses the heuristic in First_Sloc, which is then
used by Compute_Sloc.

gcc/ada/

	* exp_ch4.adb (Expand_N_Op_Ne): Simply don't add extra parens.