RFR: 8272998: ImageIO.read() throws incorrect exception type

[Phil Race]

ImageIO.read() only documents IOException for any kind of decoding problem and since
it is a convenience API we don't want to start requiring applications to handle other RuntimeExceptions.
So in the unlikely case of some problem decoding using this API, wrap any RuntimeException in
an IIOException. This will give more stable app behaviour and still report the underlying problem.

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Commit messages:
 - 8272998
 - 8272998

Changes: https://git.openjdk.org/jdk/pull/9113/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=9113&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8272998
  Stats: 158 lines in 2 files changed: 158 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/9113.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9113/head:pull/9113

PR: https://git.openjdk.org/jdk/pull/9113