Fix recent x86 pe/coff testsuite regressions
* testsuite/gas/i386/sha512-intel.d: Accept section nop padding.
* testsuite/gas/i386/sha512.d: Likewise.
* testsuite/gas/i386/sm3-intel.d: Likewise.
* testsuite/gas/i386/sm3.d: Likewise.
* testsuite/gas/i386/x86-64-pbndkb-intel.d: Likewise.
* testsuite/gas/i386/x86-64-pbndkb.d: Likewise.
* testsuite/gas/i386/x86-64-sha512-intel.d: Likewise.
* testsuite/gas/i386/x86-64-sha512.d: Likewise.
* testsuite/gas/i386/x86-64-sm3-intel.d: Likewise.
* testsuite/gas/i386/x86-64-sm3.d: Likewise.