[clang] [clang] Check validity of SYCL device target (PR #172366)

[Tom Honermann via cfe-commits]

================
@@ -0,0 +1,16 @@
+/// Check "-fsycl-is-device" and the default triple "spirv64-unknown-unknown"
+//  is passed when compiling for device.
+
+// RUN:   %clang -### -fsycl -fsycl-device-only %s 2>&1 \
+// RUN:   | FileCheck %s
+
+// CHECK: "-triple" "spirv64-unknown-unknown" {{.*}} "-fsycl-is-device"
----------------
tahonermann wrote:

Can we also validate that `-aux-triple` appears in the command line?

https://github.com/llvm/llvm-project/pull/172366