RFR: JDK-8260902: CDS mapping errors should not lead to unconditional output

[Thomas Stuefe]

There are some places where unconditional error messages are printed to tty for recoverable errors. This is not good since the VM may continue without problems, but those printouts may confuse scripts parsing the VM output, or end up at the wrong places:

See e.g.: https://mail.openjdk.java.net/pipermail/build-dev/2021-February/030256.html

One of these points are mapping errors in CDS. VM will just continue without CDS, so its not a fatal error. 

I fixed some places which clearly were non-fatal while leaving log_error in place for cases which are clearly fatal, or borderline fatal (like rs commit errors). I looked for tests which could have parsed these lines and found none.

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Commit messages:
 - Initial

Changes: https://git.openjdk.java.net/jdk/pull/2348/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2348&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8260902
  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2348.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2348/head:pull/2348

PR: https://git.openjdk.java.net/jdk/pull/2348