Create tests that coalesce the handshake messages in the first flight from
the server. This lets us test the behavior of the library when a handshake
record contains multiple handshake messages.
Only non-protected (non-encrypted, non-authenticated) handshake messages are
supported.
The test code works for all protocol versions, but it is only effective in
TLS 1.2. In TLS 1.3, there is only a single non-encrypted handshake record,
so we can't test records containing more than one handshake message without
a lot more work.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
