RFR: 8278525: Additional -Wnonnull errors happen with GCC 11

[Paul Hohensee]

On Thu, 9 Dec 2021 23:48:42 GMT, Dan Lutker <duke at openjdk.java.net> wrote:

> 8271515 introduced more issues with xmm0

Lgtm.

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Marked as reviewed by phh (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6788