[OpenMP][deviceRTLs] Added `[[clang::loader_uninitialized]]` explicitly

[tianshilei1992]

Summary

[[clang::loader_uninitialized]] is in macro SHARED but it doesn't
work for array like parallelLevel, so the variable will be zero initialized.
There is also a similar issue for omptarget_nvptx_device_State which is in
global address space. Its c'tor is also generated, which was not in the past when
building the deviceRTLs with CUDA. In this patch, we added the attribute to
the two variables explicitly.

[jdoerfert]

LG

[tianshilei1992]

rebase to triger a new round of test

[tianshilei1992]

rebased

openmp/libomptarget/deviceRTLs/common/src/omp_data.cu

 ////////////////////////////////////////////////////////////////////////////////
 
 DEVICE omptarget_device_environmentTy omptarget_device_environment;
 
 ////////////////////////////////////////////////////////////////////////////////
 // global data holding OpenMP state information
 ////////////////////////////////////////////////////////////////////////////////
 
-DEVICE
+// OpenMP will try to call its ctor if we don't add the attribute explicitly
+[[clang::loader_uninitialized]] DEVICE
     omptarget_nvptx_Queue<omptarget_nvptx_ThreadPrivateContext, OMP_STATE_COUNT>
         omptarget_nvptx_device_State[MAX_SM];
 
 DEVICE omptarget_nvptx_SimpleMemoryManager omptarget_nvptx_simpleMemoryManager;
 DEVICE uint32_t SHARED(usedMemIdx);
 DEVICE uint32_t SHARED(usedSlotIdx);
 
-DEVICE uint8_t parallelLevel[MAX_THREADS_PER_TEAM / WARPSIZE];
+// SHARED doesn't work with array so we add the attribute explicitly.
+[[clang::loader_uninitialized]] DEVICE uint8_t
+    parallelLevel[MAX_THREADS_PER_TEAM / WARPSIZE];
 #pragma omp allocate(parallelLevel) allocator(omp_pteam_mem_alloc)
 DEVICE uint16_t SHARED(threadLimit);
 DEVICE uint16_t SHARED(threadsInTeam);
 DEVICE uint16_t SHARED(nThreads);
 // Pointer to this team's OpenMP state object
 DEVICE omptarget_nvptx_ThreadPrivateContext *
     SHARED(omptarget_nvptx_threadPrivateContext);