[libc++] Implements LWG3130. (#101889)

This adds addressof at the required places in [input.output]. Some of
the new tests failed since string used operator& internally. These have
been fixed too.

Note the new fstream tests perform output to a basic_string instead of a
double. Using a double requires num_get specialization

num_get<CharT, istreambuf_iterator<CharT,
char_traits_operator_hijacker<CharT>>

This facet is not present in the locale database so the conversion would
fail due to a missing locale facet. Using basic_string avoids using the
locale.

As a drive-by fixes several bugs in the ofstream.cons tests. These
tested ifstream instead of ofstream with an open mode.

Implements:
- LWG3130 [input.output] needs many addressof

Closes #100246.

0 files changed, 0 insertions, 0 deletions