RFR: 8324129: C2: Remove some ttyLocker usages in preparation for JDK-8306767

[David Holmes]

On Thu, 18 Jan 2024 15:17:27 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

> I'm removing some instances of `ttyLocker`. Instead of locking, I first put all the output on a `stringStream`, and then print this stream all at once, which is atomic.
> 
> Removing the `ttyLocker` is nice, because it means we have less interference with other locking mechanisms, such as the `extra_data_lock` cases I have to introduce with [JDK-8306767](https://bugs.openjdk.org/browse/JDK-8306767).
> 
> @coleenp wished that I do this separately, so I filed this RFE here.

Marked as reviewed by dholmes (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/17486#pullrequestreview-1836152658