RFR: 8265484: Fix up TRAPS usage in GenerateOopMap::compute_map and callers [v2]

[David Holmes]

> If compute_map encounters malformed bytecode, or an OOM condition then it can raise a LinkageError to be thrown in regular JavaThreads, and this is reflected in the use of TRAPS in a couple of methods. But for non-JavaThreads, and compiler threads, the occurrence of such an error is treated as a fatal error and we abort the VM.
> 
> In addition, most of the callers of compute_map actually use the CATCH macro, which just clears the exception and will abort a non-product VM.
> 
> This use of TRAPS is a problem for the change to convert TRAPS to JavaThread, because these methods are called by non-JavaThreads. To address this we change compute_map to create, but not throw, the exception and return a bool indicating whether an error occurred, and the caller can then choose to throw the exception itself. 
> 
> Testing: tiers 1-3
> 
> Thanks,
> David

David Holmes has updated the pull request incrementally with one additional commit since the last revision:

  Additional comments on failure modes

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3580/files
  - new: https://git.openjdk.java.net/jdk/pull/3580/files/5681dfe4..264fbea5

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3580&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3580&range=00-01

  Stats: 6 lines in 2 files changed: 6 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3580.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3580/head:pull/3580

PR: https://git.openjdk.java.net/jdk/pull/3580