[SYCL] Disable scheduler unit tests on Windows (#20939)

Seeing sporadic fails.

Ex:
https://github.com/intel/llvm/actions/runs/20344544188/job/58453108306

Signed-off-by: Nick Sarnie <nick.sarnie@intel.com>

Author: sarnex

sycl/unittests/scheduler/CMakeLists.txt

@@ -1,3 +1,7 @@
+if(WIN32)
+  # https://github.com/intel/llvm/issues/15049
+  return()
+endif()
 add_sycl_unittest(SchedulerTests OBJECT
     BlockedCommands.cpp
     Commands.cpp