RFR: 8304290: Some JNI calls made without checking exceptions in media

[Alexander Matveev]

On Tue, 18 Apr 2023 02:08:03 GMT, Alexander Matveev <almatvee at openjdk.org> wrote:

> - Added missing exception checks for JNI calls.
>  - Improved JNI error checking by checking for both exception and return value.
>  - Minor code clean up.

8304290: Some JNI calls made without checking exceptions in media [v2]
 - Fixed latest comments.

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PR Comment: https://git.openjdk.org/jfx/pull/1094#issuecomment-1571048630