chore: adding name attr to testsuite for phpunit config

[vishwarajanand]

Fixes #5382

[vishwarajanand]

Datastore tests have been failing for reasons unknown to me and unrelated to this PR.

[vishwarajanand]

After looking deeper into the Datastore system test failure, it seems similar errors occurred in past due to regressions in GRPC, ref: #3911

Also, Datastore tests run fine on my local:

➜  Datastore git:(add_attr_name_phpunit_xmls) ✗ XDEBUG_MODE=coverage  vendor/bin/phpunit --verbose -c phpunit-system.xml.dist tests/System/AllocateKeyTest.php 
PHPUnit 8.5.27 #StandWithUkraine

Runtime:       PHP 8.1.5 with Xdebug 3.1.2
Configuration: /usr/local/google/home/vishwarajanand/github/google-cloud-php/Datastore/phpunit-system.xml.dist

....                                                                4 / 4 (100%)

Time: 193 ms, Memory: 8.00 MB

OK (4 tests, 8 assertions)
➜  Datastore git:(add_attr_name_phpunit_xmls) ✗ XDEBUG_MODE=coverage  vendor/bin/phpunit --verbose -c phpunit-system.xml.dist tests/System/CustomEntityTypeTest.php                                 
PHPUnit 8.5.27 #StandWithUkraine

Runtime:       PHP 8.1.5 with Xdebug 3.1.2
Configuration: /usr/local/google/home/vishwarajanand/github/google-cloud-php/Datastore/phpunit-system.xml.dist

..                                                                  2 / 2 (100%)

Time: 290 ms, Memory: 8.00 MB

OK (2 tests, 8 assertions)
➜  Datastore git:(add_attr_name_phpunit_xmls) ✗ XDEBUG_MODE=coverage  vendor/bin/phpunit --verbose -c phpunit-system.xml.dist tests/System/DatastoreSessionHandlerTest.php 
PHPUnit 8.5.27 #StandWithUkraine

Runtime:       PHP 8.1.5 with Xdebug 3.1.2
Configuration: /usr/local/google/home/vishwarajanand/github/google-cloud-php/Datastore/phpunit-system.xml.dist

.                                                                   1 / 1 (100%)

Time: 1.25 seconds, Memory: 8.00 MB

OK (1 test, 1 assertion)
➜  Datastore git:(add_attr_name_phpunit_xmls) ✗ XDEBUG_MODE=coverage  vendor/bin/phpunit --verbose -c phpunit-system.xml.dist tests/System/DatastoreTestCase.php          
PHPUnit 8.5.27 #StandWithUkraine

Runtime:       PHP 8.1.5 with Xdebug 3.1.2
Configuration: /usr/local/google/home/vishwarajanand/github/google-cloud-php/Datastore/phpunit-system.xml.dist

W                                                                   1 / 1 (100%)

Time: 46 ms, Memory: 8.00 MB

There was 1 warning:

1) Warning
No tests found in class "Google\Cloud\Datastore\Tests\System\DatastoreTestCase".

WARNINGS!
Tests: 1, Assertions: 0, Warnings: 1.
➜  Datastore git:(add_attr_name_phpunit_xmls) ✗ XDEBUG_MODE=coverage  vendor/bin/phpunit --verbose -c phpunit-system.xml.dist tests/System/QueryResultPaginationTest.php 
PHPUnit 8.5.27 #StandWithUkraine

Runtime:       PHP 8.1.5 with Xdebug 3.1.2
Configuration: /usr/local/google/home/vishwarajanand/github/google-cloud-php/Datastore/phpunit-system.xml.dist

........                                                            8 / 8 (100%)

Time: 4.07 seconds, Memory: 12.00 MB

OK (8 tests, 12 assertions)
➜  Datastore git:(add_attr_name_phpunit_xmls) ✗ XDEBUG_MODE=coverage  vendor/bin/phpunit --verbose -c phpunit-system.xml.dist tests/System/RunTransactionTest.php 
PHPUnit 8.5.27 #StandWithUkraine

Runtime:       PHP 8.1.5 with Xdebug 3.1.2
Configuration: /usr/local/google/home/vishwarajanand/github/google-cloud-php/Datastore/phpunit-system.xml.dist

..                                                                  2 / 2 (100%)

Time: 508 ms, Memory: 10.00 MB

OK (2 tests, 4 assertions)
➜  Datastore git:(add_attr_name_phpunit_xmls) ✗ XDEBUG_MODE=coverage  vendor/bin/phpunit --verbose -c phpunit-system.xml.dist tests/System/SaveAndModifyTest.php 
PHPUnit 8.5.27 #StandWithUkraine

Runtime:       PHP 8.1.5 with Xdebug 3.1.2
Configuration: /usr/local/google/home/vishwarajanand/github/google-cloud-php/Datastore/phpunit-system.xml.dist

............                                                      12 / 12 (100%)

Time: 934 ms, Memory: 8.00 MB

OK (12 tests, 34 assertions)
➜  Datastore git:(add_attr_name_phpunit_xmls) ✗