hg: jdk/sandbox: 8227633: avoid comparing this pointers to NULL

[chris.hegarty at oracle.com]

Changeset: fb2b47f0e067
Author:    mbaesken
Date:      2019-07-16 14:42 +0200
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/fb2b47f0e067

8227633: avoid comparing this pointers to NULL
Reviewed-by: coleenp, mdoerr

! src/hotspot/share/adlc/formssel.cpp
! src/hotspot/share/adlc/output_c.cpp
! src/hotspot/share/libadt/set.cpp