Remove finalize from TIFF ImageIO implementatation classes.

Following copied from the bug description 
The TIFF image (de)compressors can make use of a JPEG reader / writer
Like all ImageIO readers and writers, once done, the owner should call their 
dispose() method.
This is currently done with finalize() to ensure it isn't missed.

This can be migrated to a Disposer.

However, the most common case is that it is the ImageIO built-in 
JPEGImageReader and JPEGImageWriter
that is located and that already implements a Disposer. So there is no need to 
add a Disposer for that.
We only need to add it if we find some other reader/writer.

With enough work, it might be possible for the TIFF compressor/decompressor 
classes to work out when
they are really done and avoid a Disposer at all. But it could also be that 
they instead need to discard
them when a specific task is done and then obtain a new one.
That would be much more overhead than just adding a Disposer for the rare case 
and regardless
of what is done in the TIFF code, the built in JPEG classes will install their 
own Disposer so I don't
think I want to pursue that route.

I also noticed that TIFFBaseJPEGCompressor.java can replace the current writer 
if it doesn't satisfy a need.
In that case it just nulls it out and doesn't call dispose() and of course 
finalize() will then refer to the replacement.
So I added direct calls to dispose() in such a case. That was definitely 
necessary with the finalize() code
but the Disposer would have taken care of it anyway, so it isn't strictly 
needed with the new code but
it is still good to do it early if you can.

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Commit messages:
 - 8362898
 - 8362898

Changes: https://git.openjdk.org/jdk/pull/26416/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26416&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8362898
  Stats: 44 lines in 3 files changed: 31 ins; 4 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/26416.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26416/head:pull/26416

PR: https://git.openjdk.org/jdk/pull/26416

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