The JBAS-5203 must be causing some of those regressions (more probably the jca ones, not sure about the rest)

http://hudson.qa.jboss.com/hudson/view/JBoss%20AS/job/JBoss-AS-5.0.x-TestSuite-sun15/850/testReport/

org.jboss.test.jacc.test.MissingMethodUnitTestCase(JACC).testMissingIsUnchecked
org.jboss.test.jca.test.ManagedDeploymentUnitTestCase.testEmptyContentMarshal
org.jboss.test.jca.test.ManagedDeploymentUnitTestCase.testXAWithInterleavingMarshal
org.jboss.test.jca.test.XAExceptionUnitTestCase.testGetConnectionResourceError
org.jboss.test.jca.test.XAExceptionUnitTestCase.testGetConnectionRuntimeError
org.jboss.test.jca.test.XAExceptionUnitTestCase.testMatchManagedConnectionResourceError
org.jboss.test.jca.test.XAExceptionUnitTestCase.testMatchManagedConnectionRuntimeError
org.jboss.test.jca.test.XATxConnectionManagerUnitTestCase.testEnlistInExistingTx
org.jboss.test.jca.test.XATxConnectionManagerUnitTestCase.testFailedStartTx
org.jboss.test.security.test.WebConstraintsUnitTestCase(tests-security-basic-unit).testGetAccess
org.jboss.test.web.test.UserInRoleUnitTestCase.testConflictingUserInRole