hg: panama/dev: Fix reduce_add2F/reduce_add2D for incorrect associativity

[yang.zhang at arm.com]

Changeset: a385ccae8a6e
Author:    yzhang
Date:      2020-03-04 14:50 +0800
URL:       https://hg.openjdk.java.net/panama/dev/rev/a385ccae8a6e

Fix reduce_add2F/reduce_add2D for incorrect associativity
The implementation of these two nodes on AArch64 accumulate it's arguments in
the wrong order, as the addition of floating point values doesn't obey
associative law.

Contributed-by: qi.feng at arm.com

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