Restrict the address space to be local for workgroup initialization
Restrict the address space to be local for workgroup initialization

In commit Basic support of VK_KHR_zero_initialize_workgroup_memory
(95b2dfd5426d0d58ec6872a0ec3bddc21c7a6eba), the global variables with
null initializer will be initialized which is not obey to the extension.
The requirement should be shared global variable with null initializer.

GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc