[SYCL][UT] Eliminate concurrent read-write of mock callbacks map

[KseniyaTikhomirova]

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.

[KseniyaTikhomirova]

failed tests are not related. I updated only 1 UT test.

Linux: Failed Tests (1):
SYCL :: bindless_images/vulkan_interop/vulkan_sycl_image_interop_write_1d_unsampled.cpp

Windows:
Failed Tests (1):
SYCL :: Adapters/level_zero/batch_event_status.cpp
Another windows failure (hang) can't be rel;ated as well. SchedulerTests are currently completely excluded from Win scope.

[KseniyaTikhomirova]

@intel/llvm-gatekeepers hi, please consider merging this. Reported failures can't be related.