tests: Add bugpoint to MK_TEST_DIRS

Also change `-err_grep` to `-err-grep` for consistency with `-expect-return`.

tests/bugpoint/err.ys

@@ -38,6 +38,6 @@ select -assert-mod-count 1 zzy
 # raise_error -stderr prints to stderr and exits with 1
 design -load read
 rename top abc
-bugpoint -yosys ../../yosys -command "raise_error -stderr" -err_grep "help me" -expect-return 1
+bugpoint -yosys ../../yosys -command "raise_error -stderr" -err-grep "help me" -expect-return 1
 select -assert-mod-count 1 =*
 select -assert-mod-count 1 other

tests/bugpoint/run-test.sh

@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+set -eu
+source ../gen-tests-makefile.sh
+generate_mk --yosys-scripts