Build/Test Tools: Update PHPUnit configuration for PHPUnit 9.5.10/8.5…

….21+.

Since PHPUnit 9.5.10 and 8.5.21, PHP deprecations are no longer converted to exceptions by default (`convertDeprecationsToExceptions="true"` can be configured to enable this).

Reference: [sebastianbergmann/phpunit@fac0262 Do not convert PHP deprecations to exceptions by default]; [https://github.com/sebastianbergmann/phpunit/blob/9.5.10/ChangeLog-9.5.md#9510---2021-09-25 PHPUnit 9.5.10 changelog].

Let's unpack this:

Previously (PHPUnit < 9.5.10/8.5.21), if PHPUnit would encounter a PHP native deprecation notice, it would:
1. Show a test which causes a deprecation notice to be thrown as **"errored"**,
2. Show the **first** deprecation notice it encountered and
3. PHPUnit would exit with a **non-0 exit code** (2), which will fail a CI build.

As of PHPUnit 9.5.10/8.5.21, if PHPUnit encounters a PHP native deprecation notice, it will no longer do so. Instead PHPUnit will:
1. Show a test which causes a PHP deprecation notice to be thrown as **"risky"**,
2. Show the **all** deprecation notices it encountered and
3. PHPUnit will exit with a **0 exit code**, which will show a CI build as passing.

This commit reverts PHPUnit to the previous behaviour by adding `convertDeprecationsToExceptions="true"` to the PHPUnit configuration. It also adds the other related directives for consistency.

Props jrf, netweb, costdev, SergeyBiryukov.
See #54183.

git-svn-id: https://develop.svn.wordpress.org/trunk@51871 602fd350-edb4-49c9-b593-d223f7449a82

phpunit.xml.dist

@@ -6,6 +6,10 @@
 		colors="true"
 		beStrictAboutTestsThatDoNotTestAnything="true"
 		beStrictAboutOutputDuringTests="true"
+		convertErrorsToExceptions="true"
+		convertWarningsToExceptions="true"
+		convertNoticesToExceptions="true"
+		convertDeprecationsToExceptions="true"
 		>
 	<testsuites>
 		<!-- Default test suite to run all tests. -->

tests/phpunit/multisite.xml

@@ -6,6 +6,10 @@
 		colors="true"
 		beStrictAboutTestsThatDoNotTestAnything="true"
 		beStrictAboutOutputDuringTests="true"
+		convertErrorsToExceptions="true"
+		convertWarningsToExceptions="true"
+		convertNoticesToExceptions="true"
+		convertDeprecationsToExceptions="true"
 		>
 	<php>
 		<const name="WP_TESTS_MULTISITE" value="1" />