fix(datafusion): resolve temporary objects first in SHOW CREATE TABLE

[plusplusjiajia]

Purpose

A temporary table or view shadows a catalog table in queries, but SHOW CREATE TABLE in SQLContext still returned the shadowed Paimon table's DDL:

CREATE TEMPORARY VIEW paimon.db.t AS SELECT 1 AS id;
SELECT * FROM paimon.db.t;          -- reads the temporary view
SHOW CREATE TABLE paimon.db.t;      -- returned the Paimon table's DDL

Temporary objects without a catalog table were described by DataFusion through information_schema.views, which loads every table in the catalog, so an unrelated table that fails to load broke the statement.

Flink's SHOW CREATE TABLE likewise resolves temporary tables before permanent ones.

Brief change log

• Look up the temporary object first, with names normalized as in queries, and return its definition directly (NULL when it has none).
• Paimon tables without a temporary object keep the generated DDL.
• information_schema keeps resolving to DataFusion's metadata tables, as in queries.

Tests

• A temporary view or table shadowing a Paimon table returns its own definition or NULL.
• Temporary object names resolve like queries: unquoted names are normalized, quoted names are kept.
• A temporary object is described without loading an unrelated broken table.
• A temporary view named under information_schema does not change what SHOW CREATE TABLE describes.