pgsql: Use IsA() macro in define.c, for sake of consistency.

Use IsA() macro in define.c, for sake of consistency.

Commit 63d1b1cf7f1 replaced a direct nodeTag() comparison with the IsA()
macro in copy.c, but a similar direct comparison remained in define.c.

This commit replaces that comparison with IsA() for consistency.

Author: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
Reviewed-by: Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>
Reviewed-by: Shinya Kato <shinya11(dot)kato(at)gmail(dot)com>
Reviewed-by: Bertrand Drouvot <bertranddrouvot(dot)pg(at)gmail(dot)com>
Discussion: https://postgr.es/m/CAHGQGwGjWGS89_sTx=sbPm0FQemyQQrfTKm=taUhAJFV5k-9cw@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/24cb3a08a43b5a48f5fba4a83d297218e2e748c5

Modified Files
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src/backend/commands/define.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)