RFR (S) 8244200: Shenandoah: build breakages after JDK-8241743

[Aleksey Shipilev]

Bug:
  https://bugs.openjdk.java.net/browse/JDK-8244200

This looks like a regression from JDK-8241743 that moved ShenandoahHeap::heap() to .inline.hpp. To
fix it everywhere, I rolled over every file that references ShenandoahHeap::heap() and added the
relevant include. It fixes the reported build failure, and hopefully similar ones in future.

Fix:
  https://cr.openjdk.java.net/~shade/8244200/webrev.01/

Testing: Linux x86_64 {fastdebug, release, slowdebug} no-PCH builds with/without JFR

-- 
Thanks,
-Aleksey