reuse core fixture for dbt show sql header test

tests/functional/adapter/dbt_show/test_dbt_show.py

@@ -1,27 +1,9 @@
-import pytest
 from dbt.tests.adapter.dbt_show.test_dbt_show import BaseShowSqlHeader, BaseShowLimit
 
 
-my_model_sql_header_sql = """
-{{
-  config(
-    materialized = "table"
-  )
-}}
-{% call set_sql_header(config) %}
-SET MY_VARIABLE='test';
-{% endcall %}
-SELECT $MY_VARIABLE as column_name
-"""
-
-
 class TestBigQueryShowLimit(BaseShowLimit):
     pass
 
 
 class TestBigQueryShowSqlHeader(BaseShowSqlHeader):
-    @pytest.fixture(scope="class")
-    def models(self):
-        return {
-            "sql_header.sql": my_model_sql_header_sql,
-        }
+    pass