Add HiPE and ErLLVM testing

Makefile

@@ -12,6 +12,8 @@ PLT_APPS = public_key ssl
 CT_OPTS += -ct_hooks cowboy_ct_hook [] # -boot start_sasl
 
 CI_OTP ?= OTP-18.0.3 OTP-18.1.5 OTP-18.2.4.1 OTP-18.3.4.4 OTP-19.0.7 OTP-19.1.5
+CI_HIPE ?= $(lastword $(CI_OTP))
+CI_ERLLVM ?= $(CI_HIPE)
 
 # Dependencies.