git: openjdk/jdk11u-dev: 8223140: Clean-up in 'ok_to_convert()'

[Goetz Lindenmaier]

Changeset: 45d63a86
Author:    Goetz Lindenmaier <goetz at openjdk.org>
Date:      2021-10-06 07:28:46 +0000
URL:       https://git.openjdk.java.net/jdk11u-dev/commit/45d63a86326bd9cf36458b2c536b5f6fd8375d5e

8223140: Clean-up in 'ok_to_convert()'

Simplify logic in function. Added precond/postcond macros.

Reviewed-by: shade
Backport-of: f4faee7bae5bdfcae994e95dc7e4e53ba850db98

! src/hotspot/share/opto/loopnode.cpp
! src/hotspot/share/opto/node.hpp
! src/hotspot/share/opto/subnode.cpp