added test support for databases without boolean types (#4091)

* added support for dbs without boolean types

* catch errors a bit better

* moved changelog entry

* fixed tests and updated exception

* cleaned up bool check

* added positive test, removed self ref

automatic commit by git-black, original commits:
  a5ce658
  eace5b7

core/dbt/task/test.py

@@ -25,9 +25,7 @@
     PrintPassTestResult,
     PrintWarnTestResult,
     PrintFailureTestResult,
-    InternalException,
-    invalid_bool_error,
-    missing_materialization
+    PrintStartLine,
 )
 from dbt.exceptions import InternalException, invalid_bool_error, missing_materialization
 from dbt.graph import (