This seems to be a simple oversight, where we did not enable
exceptions. Other constexpr conditions already throw, so there is
no particular reason to stick to a fatal error here.

The $Id$ keywords were used in Subversion where they can be substituted
with filename, last revision number change, last changed date, and last
user who changed it.

In Git this functionality is different and can be done with Git attribute
ident. These need to be defined manually for each file in the
.gitattributes file and are afterwards replaced with 40-character
hexadecimal blob object name which is based only on the particular file
contents.

This patch simplifies handling of $Id$ keywords by removing them since
they are not used anymore.

In PHP static properties are shared between inheriting classes,
unless they are explicitly overwritten. However, because this
functionality was implemented using reference, it was possible
to break the implementation by reassigning the static property
reference.

This is fixed by switching the implementation from using references
to using INDIRECTs, which cannot be affected by userland code.

- Avoid iterators check/update on each HashTable update opration
- Keep position equal (or above) nNumUsed instead of HT_INVALID_IDX
- Fixed iterators handling in array_unshift()

EXPECTF logic in run-tests.php is considerable, so let's avoid it.