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

[Emanuel Peter]

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.

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Commit messages:
 - 8324129

Changes: https://git.openjdk.org/jdk/pull/17486/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17486&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324129
  Stats: 73 lines in 11 files changed: 14 ins; 2 del; 57 mod
  Patch: https://git.openjdk.org/jdk/pull/17486.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17486/head:pull/17486

PR: https://git.openjdk.org/jdk/pull/17486