[11] RFC 8247824: CTW: C2 (Shenandoah) compilation fails with SEGV in SBC2Support::pin_and_expand

[Aleksey Shipilev]

Hi,

We have this bug:
  https://bugs.openjdk.java.net/browse/JDK-8247824
  https://hg.openjdk.java.net/jdk/jdk15/rev/95946afeaad1

...and it reproduces with 11u, so backporting it is in order. The patch applies cleanly to 11u, but
one of the hunks adds new code in loopnode.hpp. My question is: should it be protected by
INCLUDE_SHENANDOAHGC and/or UseShenandoahGC?

-- 
Thanks,
-Aleksey