test: Add a test case for #1745

Author: andrewmbenton

internal/endtoend/testdata/select_system/issue.md

@@ -0,0 +1 @@
+https://github.com/sqlc-dev/sqlc/issues/1745

internal/endtoend/testdata/select_system/stdlib/query.sql

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+-- name: GetCtId :one
+SELECT ctid FROM test;

internal/endtoend/testdata/select_system/stdlib/schema.sql

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+CREATE TABLE test (
+  id INT
+);

internal/endtoend/testdata/select_system/stdlib/sqlc.yaml

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+version: "2"
+cloud:
+  project: "01HAQMMECEYQYKFJN8MP16QC41"
+sql:
+  - engine: "postgresql"
+    schema: "schema.sql"
+    queries: "query.sql"
+    gen:
+      go:
+        package: "querytest"
+        out: "go"
+        sql_package: "database/sql"
+    database:
+      managed: true