1956 adds the sha256 value corresponding to an empty buffer
1957 adds an arbitrary value and confirms that the signature differs from 1956
1958 adds whitespace to 1957 and confirms that the signature matches 1957
1959 adds a value longer than 'char sha_hex[65]' in Curl_output_aws_sigv4()
Signed-off-by: Casey Bodley <cbodley@redhat.com>
Closes#9804
