x86: Terminate mnemonicendp in swap_operand()

x86: Terminate mnemonicendp in swap_operand()

Tested on x86_64-pc-linux-gnu.

opcodes/ChangeLog:
2021-12-17 Vladimir Mezentsev <vladimir.mezentsev@oracle.com>

	* i386-dis.c (swap_operand): Terminate mnemonicendp.

gas/ChangeLog:
2021-12-17 Vladimir Mezentsev <vladimir.mezentsev@oracle.com>

	* testsuite/gas/i386/opts-intel.d: Updated expected disassembly.
	* testsuite/gas/i386/opts.d: Likewise.
	* testsuite/gas/i386/sse2avx-opts-intel.d: Likewise.
	* testsuite/gas/i386/sse2avx-opts.d: Likewise.
	* testsuite/gas/i386/x86-64-opts-intel.d: Likewise.
	* testsuite/gas/i386/x86-64-opts.d: Likewise.
	* testsuite/gas/i386/x86-64-sse2avx-opts-intel.d: Likewise.
	* testsuite/gas/i386/x86-64-sse2avx-opts.d: Likewise.