[OpenJDK 2D-Dev] RFR: 8149810: TIFFField#getAsLong throws ClassCastException when data is type TIFFTag.TIFF_DOUBLE or TIFFTag.FLOAT

[Brian Burkhalter]

Please review at your convenience:

Issue:  https://bugs.openjdk.java.net/browse/JDK-8149810
Patch:  http://cr.openjdk.java.net/~bpb/8149810/webrev.00/

Summary:
1) Fix the code which caused the exception.
2) Update the specification of getAsLong() to be similar to that of getAsInt(), 
i.e., complete and accurate.

Thanks,

Brian