RFR: Fix shenandoah jdk non-PCH build

[Zhengyu Gu]

The patch to fix shenandoah jdk build with precompiled header disabled.

Webrev: http://cr.openjdk.java.net/~zgu/shenandoah/sh-jdk-non-PCH/webrev.00/


Test:

   hotspot_gc_shenandoah (fastdebug and release)

Thanks,

-Zhengyu