RFR: 8337960: Improve performance of mfwrapper by reusing GStreamer media buffers for decoded video

[Alexander Matveev]

- Added new class `CMFGSTBuffer` which can allocate memory internally or provide GStreamer allocated memory to Media Foundation.
- Added `GstBufferPool` to limit allocation of output buffers used for rendering (memory will not be allocated for each buffer, but instead will be reused from pool). Limits are 3 min buffers and 6 max buffers. During testing 3 buffers was enough.
- Changed `CoInitializeEx` to `COINIT_MULTITHREADED` as per Media Foundation requirements.
- Added error handling for `ProcessOutput` in case of https://bugs.openjdk.org/browse/JDK-8329227. With error handling `MediaPlayer` fails nicely instead of silent hang.

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Commit messages:
 - 8337960: Improve performance of mfwrapper by reusing GStreamer media buffers for decoded video

Changes: https://git.openjdk.org/jfx/pull/1695/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1695&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337960
  Stats: 842 lines in 8 files changed: 592 ins; 64 del; 186 mod
  Patch: https://git.openjdk.org/jfx/pull/1695.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1695/head:pull/1695

PR: https://git.openjdk.org/jfx/pull/1695