SWDEV-1 - Fix warnings and update disabled test list (#163)

- Fix warnings in some test cases due to unused variables or signed/unsigned comparison.
- Disabled vulkan tests on MI200.

catch/unit/memory/hipPointerGetAttributes.cc

@@ -213,12 +213,10 @@ TEST_CASE("Unit_hipPointerGetAttributes_Basic") {
 
   char* A_d;
   char* A_Pinned_h;
-  char* A_OSAlloc_h;
   hipError_t e;
 
   HIP_CHECK(hipMalloc(&A_d, Nbytes));
   HIP_CHECK(hipHostMalloc(reinterpret_cast<void**>(&A_Pinned_h), Nbytes, hipHostMallocDefault));
-  A_OSAlloc_h = reinterpret_cast<char*>(malloc(Nbytes));
 
   size_t free, total;
   HIP_CHECK(hipMemGetInfo(&free, &total));