Add new 'sharedmem' kernel

tests/opencl/sharedmem/kernel.cl

@@ -0,0 +1,13 @@
+__kernel void sharedmem (__global volatile const float *src,
+						 __global volatile float *dst,
+						 __local volatile float *smem)
+{
+  int gid = get_global_id(0);
+  smem[gid] = src[gid];
+  float read;
+  __attribute__((opencl_unroll_hint))
+  for (int i = 0; i < 500; i++) {
+	  read = smem[gid];
+  }
+  dst[gid] = read;
+}