[SYCL] Fix MemObjRemapping for devices without host unified memory (#167)

The check for host unified memory within the test was insufficient,
since the use of FileCheck ignores it. Instead, force the runtime to
behave as if all devices support host unified memory for this test.

Author: sergey-semenov

SYCL/Scheduler/MemObjRemapping.cpp

@@ -1,6 +1,6 @@
 // RUN: %clangxx -fsycl %s -o %t.out
-// RUN: env SYCL_PI_TRACE=2 %CPU_RUN_PLACEHOLDER %t.out 2>&1 %CPU_CHECK_PLACEHOLDER
-// RUN: env SYCL_PI_TRACE=2 %GPU_RUN_PLACEHOLDER %t.out 2>&1 %GPU_CHECK_PLACEHOLDER
+// RUN: env SYCL_HOST_UNIFIED_MEMORY=1 SYCL_PI_TRACE=2 %CPU_RUN_PLACEHOLDER %t.out 2>&1 %CPU_CHECK_PLACEHOLDER
+// RUN: env SYCL_HOST_UNIFIED_MEMORY=1 SYCL_PI_TRACE=2 %GPU_RUN_PLACEHOLDER %t.out 2>&1 %GPU_CHECK_PLACEHOLDER
 // XFAIL: cuda
 #include <CL/sycl.hpp>
 #include <cassert>
@@ -16,9 +16,6 @@ class Bar;
 // read-write.
 int main() {
   queue Q;
-  // Mapping is not used for devices without host unified memory support.
-  if (!Q.get_device().get_info<info::device::host_unified_memory>())
-    return 0;
 
   std::size_t Size = 64;
   range<1> Range{Size};