[SYCL][ESIMD][EMU] XFAIL marking for 'esimd_merge.cpp' test (#820)

- due to memory corruption failure from piextUSMFree

Author: dongkyunahn-intel

SYCL/ESIMD/api/esimd_merge.cpp

@@ -7,6 +7,8 @@
 //===----------------------------------------------------------------------===//
 // REQUIRES: gpu
 // UNSUPPORTED: cuda || hip
+// TODO: esimd_emulator fails due to memory corruption error from piextUSMFree
+// XFAIL: esimd_emulator
 // RUN: %clangxx -fsycl %s -o %t.out
 // RUN: %GPU_RUN_PLACEHOLDER %t.out