RFR: 8311508: ZGC: RAII use of IntelJccErratumAlignment

[Aleksey Shipilev]

On Tue, 8 Aug 2023 13:49:24 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

> Fixed the locations where unnamed IntelJccErratumAlignment circumvented the correctness asserts.
> Also strengthened the asserts so that a IntelJccErratumAlignment RAII object scope must surround at least some instruction. 
> 
> Tested GHA and tier1,tier2

Looks fine. There is no functional change, only the assert that verifies the destructor actually runs after the "protected" instructions emitted.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15191#pullrequestreview-1567604075