* PHP-7.3:
  Fix #77423: parse_url() will deliver a wrong host to user

`phar_path_check()` already strips a leading slash, so we must not
attempt to strip the trailing slash from an now empty directory name.

Closes GH-6508.

Like the test title and some comments in this test describe, this test
was supposed to have `::prepare()` failing because `LOAD DATA INFILE`
would not be supported as prepared statement, and then the test checks
whether follow-up queries would succeed.  However, `LOAD DATA INFILE`
is supported for prepared statements at least on Windows with mysqlnd,
so the test does no longer test what it is supposed to do.  Therefore,
we drop it.

Closes GH-6509.

When we receive an error while reading a result set, we should
assume that no more result sets are available. libmysqlclient
implements the same behavior.

Consume any additional result sets when running INIT_COMMAND.

Given the number of duplicates this bug report had, it seems
worthwhile to fix this on PHP-7.4 as well.

Cherry-pick of 106e7e4bca7c0fd975eb219b18e3c34957ba8657.

Handle errors during next_result in exec.

When `php_zlib_deflate_filter()` is called with `PSFS_FLAG_FLUSH_INC`
but without new buckets being available (e.g. because a user calls
`rewind()` after writing to the stream), we have to make sure that any
pending data are flushed.  This could basically be done like in the
attached patch[1], but that could cause unnessary flushes, which can be
harmful for compression, and adds unnecessary flush markers to the
stream.  Thus, we use the `php_zlib_filter_data.finished` field, which
has not been used for `zlib.deflate` filters, and properly keep track
of the need to flush.

[1] <https://bugs.php.net/patch-display.php?bug_id=48725&patch=zlib-filter-flush-fix.patch&revision=latest>

Closes GH-6019.

Reading from a stream may return greater than zero, but nonetheless the
stream's EOF flag may have been set.  We have to cater to this
condition by setting the close flag for filters.

We also have to cater to that change in the zlib.inflate filter:

If `inflate()` is called with flush mode `Z_FINISH`, but the output
buffer is not large enough to inflate all available data, it fails with
`Z_BUF_ERROR`.  However, `Z_BUF_ERROR` is not fatal; in fact, the zlib
manual states: "If deflate returns with Z_OK or Z_BUF_ERROR, this
function must be called again with Z_FINISH and more output space
(updated avail_out) but no more input data, until it returns with
Z_STREAM_END or an error."  Hence, we do so.

Closes GH-6001.