Add a debug option for setting bogus H2 settings so VTC's dont

have to test with 16k frame sizes.

bin/varnishd/http2/cache_http2_proto.c

@@ -325,7 +325,8 @@ h2_set_setting(struct h2_sess *h2, const uint8_t *d)
 		VSLb(h2->vsl, SLT_Debug, "H2SETTING invalid %s=0x%08x",
 		    s->name, y);
 		AN(s->range_error);
-		return (s->range_error);
+		if (!DO_DEBUG(DBG_H2_NOCHECK))
+			return (s->range_error);
 	}
 	VSLb(h2->vsl, SLT_Debug, "H2SETTING %s=0x%08x", s->name, y);
 	AN(s->setfunc);

include/tbl/debug_bits.h

@@ -46,6 +46,7 @@ DEBUG_BIT(WITNESS,		witness,	"Emit WITNESS lock records")
 DEBUG_BIT(VSM_KEEP,		vsm_keep,	"Keep the VSM file on restart")
 DEBUG_BIT(DROP_POOLS,		drop_pools,	"Drop thread pools (testing)")
 DEBUG_BIT(SLOW_ACCEPTOR,	slow_acceptor,	"Slow down Acceptor")
+DEBUG_BIT(H2_NOCHECK,		h2_nocheck,	"Disable various H2 checks")
 #undef DEBUG_BIT
 
 /*lint -restore */