Revert "Avoid building and archiving the x86-64 pnacl-sz.nexe."
Revert "Avoid building and archiving the x86-64 pnacl-sz.nexe."

This reverts commit add84fa7c86ad027cb72ffdbf604a636a004544a.

That commit was CL https://codereview.chromium.org/987393003 .

Reverting now that pnacl-sz can produce x86-64 nexes.

This is needed in particular for measuring the Subzero sandboxed translator on the spec bots.

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4077

Review URL: https://codereview.chromium.org/1697873003

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client