Attempt to fix failing unit tests that use runInSeparateProcess

tests/phpunit_php83.patch

@@ -0,0 +1,11 @@
+--- a/src/Util/PHP/Template/TestCaseMethod.tpl.dist
++++ b/src/Util/PHP/Template/TestCaseMethod.tpl.dist
+@@ -56,7 +56,7 @@
+     }
+ 
+     @rewind(STDOUT); /* @ as not every STDOUT target stream is rewindable */
+-    if ($stdout = stream_get_contents(STDOUT)) {
++    if ($stdout = @stream_get_contents(STDOUT)) {
+         $output = $stdout . $output;
+     }
+