RFR: 8308537: Remove BreakAtNode

[Eric Nothum]

The BreakAtNode flag was unused as its utility is now insignificant with the use of "rr" in practice. See the following discussion: https://github.com/openjdk/jdk/pull/13767#issuecomment-1541805032. I removed the BreakAtNode flag and the related parts in the code.

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Commit messages:
 - 8308537: removed most of set_debug_orig(), as the most of the function was only executed when BreakAtNode was not 0, i.e. BreakAtNode was used and not set to default
 - 8308537: Removed BreakAtNode flag

Changes: https://git.openjdk.org/jdk/pull/14311/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14311&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308537
  Stats: 20 lines in 2 files changed: 0 ins; 20 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14311.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14311/head:pull/14311

PR: https://git.openjdk.org/jdk/pull/14311