x86: adjust an ILP32 testcase using .insn

In commit 6967633c8b ("x86: convert testcases to use .insn") an ILP32
clone of a testcase was missed in the set of tests needing --divide
added.

Reported-by: Clément Chigot <chigot@adacore.com>

gas/testsuite/gas/i386/ilp32/x86-64-opcode.d

@@ -1,5 +1,5 @@
 #source: ../x86-64-opcode.s
-#as: -J
+#as: -J --divide
 #objdump: -drw
 #name: x86-64 (ILP32) opcode
 #dump: ../x86-64-opcode.d