minor #51534 [DoctrineBridge][Security] Rename loadUserByUsername tests to loadUserByIdentifier (alamirault)

This PR was merged into the 6.3 branch.

Discussion
----------

[DoctrineBridge][Security] Rename `loadUserByUsername` tests to `loadUserByIdentifier`

| Q             | A
| ------------- | ---
| Branch?       | 6.3
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tickets       | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->

Tests use `loadUserByIdentifier` method but name were `loadUserByUsername` (legacy)

Commits
-------

e32c833e04 [DoctrineBridge][Security] Rename loadUserByUsername tests to loadUserByIdentifier

Author: fabpot

Tests/User/ChainUserProviderTest.php

@@ -23,7 +23,7 @@
 
 class ChainUserProviderTest extends TestCase
 {
-    public function testLoadUserByUsername()
+    public function testLoadUserByIdentifier()
     {
         $provider1 = $this->createMock(InMemoryUserProvider::class);
         $provider1
@@ -45,7 +45,7 @@ public function testLoadUserByUsername()
         $this->assertSame($account, $provider->loadUserByIdentifier('foo'));
     }
 
-    public function testLoadUserByUsernameThrowsUserNotFoundException()
+    public function testLoadUserByIdentifierThrowsUserNotFoundException()
     {
         $this->expectException(UserNotFoundException::class);
         $provider1 = $this->createMock(InMemoryUserProvider::class);

Tests/User/InMemoryUserProviderTest.php

@@ -68,7 +68,7 @@ public function testCreateUserAlreadyExist()
         $provider->createUser(new InMemoryUser('fabien', 'foo'));
     }
 
-    public function testLoadUserByUsernameDoesNotExist()
+    public function testLoadUserByIdentifierDoesNotExist()
     {
         $this->expectException(UserNotFoundException::class);
         $provider = new InMemoryUserProvider();