test: run MutexPriorityProtectOperationsTestCase at priority 1
test: move actual test code of MutexPriorityProtectOperationsTestCase
from testRunner_() to local testInvalidLockAttempt()
test: rename testRunner_() to testRunner() in some mutex test cases
ThreadBase: expose getEffectivePriority() from base class
Thread: expose getEffectivePriority() from base class
StaticThread: expose getEffectivePriority() from base class
ThisThread: add getEffectivePriority()
test: add testing of changes of priority resulting from locking mutexes
with PriorityProtect protocol in MutexPriorityProtectOperationsTestCase