RFR(XXS) 8202079: [s390]: Build failure w/o precompiled headers

[Schmidt, Lutz]

Hi,

may I please request reviews for this tiny change, adding just a missing include? 

Bug:    https://bugs.openjdk.java.net/browse/JDK-8202079
Webrev: http://cr.openjdk.java.net/~lucy/webrevs/8202079.00/ 

With this fix, the no_pch build completes OK. Due to the simplicity of the fix, I did not run extensive tests. SPECjvm98 was the most elaborate one. 

Thank you!
Lutz