RFR: 8262329: Fix JFR parser exception messages [v2]

[Roman Kennke]

> I've been irritated by unreasonable large constant pool offsets in ChunkParser excepion messages. It turns out that lastCP + size concatenates the two numbers as strings instead of adding them.
> 
> Testing:
>  - [x] manually inspecting the exception messages

Roman Kennke has updated the pull request incrementally with one additional commit since the last revision:

  Correctly compare strings

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2714/files
  - new: https://git.openjdk.java.net/jdk/pull/2714/files/33b8bec7..a0ba7f7f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2714&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2714&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2714.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2714/head:pull/2714

PR: https://git.openjdk.java.net/jdk/pull/2714