Call wally_init(0) on startup to enabled assembly-optimised SHA-256

We probably also want to call secp_randomise/wally_secp_randomize here
too, and since these calls all call setup_tmpctx, it probably makes
sense to have a helper function to do all that. Until thats done, I
modified the tests so grepping will show the places where the sequence
of calls is repeated.

Signed-off-by: Jon Griffiths <jon_p_griffiths@yahoo.com>

common/daemon.c

@@ -128,6 +128,7 @@ void daemon_setup(const char *argv0,
 
 	/* We handle write returning errors! */
 	signal(SIGPIPE, SIG_IGN);
+	wally_init(0);
 	secp256k1_ctx = wally_get_secp_context();
 
 	setup_tmpctx();