BUILD: Makefile: exclude broken tests by default

it could be sometimes a bit confusing to have tests which are known to
be broken executed in the default `make reg-tests` command, especially
for not frequent contributors which are not necessarily aware of all our
quirks.

without this patch, this test is failing on my side:
  #    top  TEST reg-tests/seamless-reload/abns_socket.vtc FAILED (2.228) exit=2
  1 tests failed, 0 tests skipped, 107 tests passed

Signed-off-by: William Dauchy <wdauchy@gmail.com>
(cherry picked from commit 3bad3d5ee64caec53077018a848075bdc817580e)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/Makefile b/Makefile
index 5b061a5..bbc36cc 100644
--- a/Makefile
+++ b/Makefile
@@ -1030,6 +1030,7 @@
 	@echo 'OBJS="$(strip $(OBJS))"'
 
 ifeq (reg-tests, $(firstword $(MAKECMDGOALS)))
+  REGTESTS_TYPES := default,bug,devel,slow
   REGTEST_ARGS := $(wordlist 2, $(words $(MAKECMDGOALS)), $(MAKECMDGOALS))
   $(eval $(REGTEST_ARGS):;@true)
 endif