c++: Make convert_like complain about bad ck_ref_bind again [PR95789]

c++: Make convert_like complain about bad ck_ref_bind again [PR95789]

convert_like issues errors about bad_p conversions at the beginning
of the function, but in the ck_ref_bind case, it only issues them
after we've called convert_like on the next conversion.

This doesn't work as expected since r10-7096 because when we see
a conversion from/to class type in a template, we return early, thereby
missing the error, and a bad_p conversion goes by undetected.  That
made the attached test to compile even though it should not.

I had thought that I could just move the ck_ref_bind/bad_p errors
above to the rest of them, but that regressed diagnostics because
expr then wasn't converted yet by the nested convert_like_real call.

So, for bad_p conversions, do the normal processing, but still return
the IMPLICIT_CONV_EXPR to avoid introducing trees that the template
processing can't handle well.  This I achieved by adding a wrapper
function.

gcc/cp/ChangeLog:

	PR c++/95789
	PR c++/96104
	PR c++/96179
	* call.c (convert_like_real_1): Renamed from convert_like_real.
	(convert_like_real): New wrapper for convert_like_real_1.

gcc/testsuite/ChangeLog:

	PR c++/95789
	PR c++/96104
	PR c++/96179
	* g++.dg/conversion/ref4.C: New test.
	* g++.dg/conversion/ref5.C: New test.
	* g++.dg/conversion/ref6.C: New test.