RFR: 8307139: Fix signed integer overflow in compiler code, part 1 [v2]

[Dean Long]

> These changes attempt to fix signed overflow caught by running tier1 with -ftrapv.  I expect more changes will be needed.
> Most of the fixes are straight-forward and involve using unsigned or java_* functions that wrap.  However, I did try to improve the usefulness of _debug_idx because as it was the high digits of the value were monotonic but unpredictable.  Now the high digits use the compile_id, which seems like an improvement.

Dean Long has updated the pull request incrementally with one additional commit since the last revision:

  make room for all digits of _idx in debug_idx

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13767/files
  - new: https://git.openjdk.org/jdk/pull/13767/files/9f1c5168..41f141ed

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13767&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13767&range=00-01

  Stats: 14 lines in 4 files changed: 0 ins; 3 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/13767.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13767/head:pull/13767

PR: https://git.openjdk.org/jdk/pull/13767