* PHP-7.4:
  Fix #73927: phpdbg fails with windows error prompt at "watch array"

We expect zvals, so we should request zvals.

We also suppress spurious watchpoint removal notices.

* PHP-7.4:
  Enable phpdbg tests on AppVeyor
  Make phpdbg test portable
  Fix several mostly Windows related phpdbg bugs
  Fix #73926: phpdbg will not accept input on restart execution

* Properly initialize PHPDBG_G(watch_tmp)

  Otherwise that may cause segfaults in ZTS builds.

* Deactivate potentially remaining watchpoints after REPL

  Otherwise the memory could still be protected, resulting in segfaults
  during shutdown.

* NULL zend_handlers_table after freeing

  As of commit 4130fe4[1], the `zend_handlers_table` is explicitly
  freed in the `zend_vm_dtor()`.  Since phpdbg (and maybe some other
  SAPIs) may restart the engine afterwards, we have to make sure that
  the table is also NULLed.

* Only set context option if there is a context

  In other words, we must not follow the null pointer.

* Cater to file handles without attached console

  File handles do not necessarily have an attached console (for
  instance, pipes do not), in which case `GetConsoleScreenBufferInfo()`
  fails.  In this case we set a default value (`40`) for lines like on
  other systems.

[1] <http://git.php.net/?p=php-src.git;a=commit;h=4130fe437a5db7ead1444d3748bd0fbad9829cb2>

Unlike the hash apply functions, these do not return int.

Closes GH-4732.

Uses system allocator when backing up settings ... let's avoid
unnecessary confusion.