Enable BF16 unary full tests in CTS

By increasing size of tensors for LOG, EXP, RECIPROCAL, SIN & COS
this will create a large enough tensor to test all BF16 values.

Change-Id: Ibb17d93b1a935fa8768f4e0f9c0baa52682327e4
Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>