Add "-fsycl-device-only" to ESIMD diagnostics tests

The reason for the change is that "-verify" mode does not work correctly
with new integration footer approach, because it seems to ignore line
markers in the input file.

Since ESIMD tests for diagnostic messages only check device APIs and
device compilation is the first step in our compilation flow, added
"-fsycl-device-only" to avoid launching the host compilation.

The positive side of this change is that now those tests should be a bit
quicker as they do less work. The downside would be that we don't check
for diagnostics coming out of host compilation.

Author: AlexeySachkov

sycl/test/esimd/enums.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// RUN: %clangxx -fsycl -fsycl-device-only -fsyntax-only -Xclang -verify %s
 
 // This test checks compilation of various ESIMD enum types. Those which are
 // deprecated must produce deprecation messages.

sycl/test/esimd/flat_atomic.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// RUN: %clangxx -fsycl -fsycl-device-only -fsyntax-only -Xclang -verify %s
 
 // This test checks compilation of ESIMD atomic APIs. Those which are deprecated
 // must produce deprecation messages.

sycl/test/esimd/gather4_scatter4.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// RUN: %clangxx -fsycl -fsycl-device-only -fsyntax-only -Xclang -verify %s
 
 // This test checks compilation of ESIMD slm gather4/scatter4 APIs. Those which
 // are deprecated must produce deprecation messages.

sycl/test/esimd/simd_copy_to_copy_from.cpp

@@ -1,6 +1,6 @@
-// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// RUN: %clangxx -fsycl -fsycl-device-only -fsyntax-only -Xclang -verify %s
 
-// This test checks that both host and device compilers can:
+// This test checks that device compiler can:
 // - successfully compile simd::copy_to and simd::copy_from APIs
 // - emit an error if argument of an incompatible type is used
 //   in place of the accessor argument

sycl/test/esimd/slm_atomic.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// RUN: %clangxx -fsycl -fsycl-device-only -fsyntax-only -Xclang -verify %s
 
 // This test checks compilation of ESIMD slm atomic APIs. Those which are
 // deprecated must produce deprecation messages.

sycl/test/esimd/slm_load4.cpp

@@ -1,4 +1,4 @@
-// RUN: %clangxx -fsycl -fsyntax-only -Xclang -verify %s
+// RUN: %clangxx -fsycl -fsycl-device-only -fsyntax-only -Xclang -verify %s
 
 // This test checks compilation of ESIMD slm load4/store4 APIs. Those which are
 // deprecated must produce deprecation messages.