PHP 8.1: fix deprecation warnings about incorrect default values

[jrfnl]

To "ignore" an optional parameter when another optional parameter after it needs to be passed, the default value should be passed, not null.

PHP 8.1/Tests: fix some deprecation warnings

The default value for the preg_split() $limit parameter is -1, not null.

Fixes numerous preg_split(): Passing null to parameter #3 ($limit) of type int is deprecated notices when running the test suite.

Ref: https://www.php.net/manual/en/function.preg-split.php

PHP 8.1/NoProxyPattern: fix deprecation warning

The default value for the preg_split() $limit parameter is -1, not null.

Fixes some preg_split(): Passing null to parameter #3 ($limit) of type int is deprecated notices when running the test suite.

Deprecation triggered by Composer\Test\Util\Http\ProxyManagerTest::testGetProxyForRequest:
preg_split(): Passing null to parameter #3 ($limit) of type int is deprecated

Stack trace:
0 [internal function]: Symfony\Bridge\PhpUnit\DeprecationErrorHandler->handleError(8192, '...', '...', 42)
1 src/Composer/Util/NoProxyPattern.php(42): preg_split('...', '...', NULL, 1)
2 src/Composer/Util/Http/ProxyManager.php(148): Composer\Util\NoProxyPattern->__construct('...')
3 src/Composer/Util/Http/ProxyManager.php(50): Composer\Util\Http\ProxyManager->initProxyData()
4 src/Composer/Util/Http/ProxyManager.php(59): Composer\Util\Http\ProxyManager->__construct()
5 tests/Composer/Test/Util/Http/ProxyManagerTest.php(75): Composer\Util\Http\ProxyManager::getInstance()
...

Ref: https://www.php.net/manual/en/function.preg-split.php

PHP 8.1: fix deprecation warnings / http_build_query()

This fixes all relevant calls to the PHP native http_build_query() function.
The second parameter of which is the optional $numeric_prefix parameter which expects a string.

A parameter being optional, however, does not automatically make it nullable.

As of PHP 8.1, passing null to a non-nullable PHP native function will generate a deprecation notice.
In this case, these function calls yielded a http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated notice.

Changing the null to an empty string fixes this without BC-break.

Fixes a few deprecation warnings found when running the tests.

Refs:

• https://www.php.net/manual/en/function.http-build-query.php
• https://wiki.php.net/rfc/deprecate_null_to_scalar_internal_arg

PHP 8.1: fix deprecation notices / PharData::__construct()

This fixes all relevant calls to the PHP native PharData::__construct() method.

The second parameter of this method is the optional $flags parameter which expects an int of flags to be passed to the Phar parent class RecursiveDirectoryIterator.
Fixed by passing the default value for the $flags parameter as per the RecursiveDirectoryIterator::__construct() method.

The third parameter of the method is the optional $alias parameter which expects an string.
Fixed by passing an empty string.

Fixes various notices along the lines of:

Deprecation triggered by Composer\Test\Package\Archiver\ArchiveManagerTest::testArchiveTar:
PharData::__construct(): Passing null to parameter #2 ($flags) of type int is deprecated

Stack trace:
0 [internal function]: Symfony\Bridge\PhpUnit\DeprecationErrorHandler->handleError(8192, '...', '...', 55)
1 src/Composer/Package/Archiver/PharArchiver.php(55): PharData->__construct('...', NULL, NULL, 2)
2 src/Composer/Package/Archiver/ArchiveManager.php(193): Composer\Package\Archiver\PharArchiver->archive('...', '...', '...', Array, false)
3 tests/Composer/Test/Package/Archiver/ArchiveManagerTest.php(65): Composer\Package\Archiver\ArchiveManager->archive(Object(Composer\Package\CompletePackage), '...', '...')
...

Refs:

• https://www.php.net/manual/en/phardata.construct.php
• https://www.php.net/manual/en/recursivedirectoryiterator.construct.php

[jrfnl]

I've added a few more commits to this PR which address similar issues (incorrect value passed for skipped optional param) in other places in the code base.
Updated the PR title and description to match.

[Seldaek]

Thanks!