Fix coverity nit in handshake_helper.c

There's no reason to wrap this call in TEST_true() if we're not
checking the return value of TEST_true() -- all of the surrounding
similar calls do not have the macro wrapping them.

Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4873)
1 file changed