[SYCL][UT] Eliminate concurrent read-write of mock callbacks map (#22872)
Initial test implementation allowed concurrent read and write of
"before_callbacks" map. After the first part of test where host task is
present Q.wait() guarantees all HT work to be finished but some post
processing (including memory release) can continue. That post processing
can call UR methods (e.g. urEventRelease and others) if needed (read
access). The second part of test was updating one of the maps in ur mock
(write access). This behavior is UB.
Split test to 2 separate tests to remove incorrect usage of UR mock
functionality.
Signed-off-by: Tikhomirova, Kseniya <kseniya.tikhomirova@intel.com>