RFR(S): 8191863: [s390] Fix CDS: some bytecode rewriting doesn't depend on RewriteControl

[Volker Simonis]

Hi,

can I please have a review for the following small, s390-only change
which fixes CDS on s390:

http://cr.openjdk.java.net/~simonis/webrevs/2017/8191863/
https://bugs.openjdk.java.net/browse/JDK-8191863

The problem was that mistakenly rewrote zputfield into fast_zputfield
although the active RewriteControl instance indicated that we
shouldn't rewrite bytecodes.

With this change, all the CDS and upcoming AppCDS jtreg pass on Linux/s390.

Thank you and best regards,
Volker