target/i386: assert that cc_op* and pc_save are preserved

target/i386: assert that cc_op* and pc_save are preserved

Now all decoding has been done before any code generation.
There is no need anymore to save and restore cc_op* and
pc_save but, for the time being, assert that this is indeed
the case.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>