Integrated: 8254879: Implement JNI path for Draw Poly

[Jayathirth D V]

When RenderQueueBuffer cant hold all the attributes needed for DrawPoly we pass the content directly to Renderer using
JNI. This path is not implemented in metal and looks like we are not hitting this path in our testing in Metal. JNI
method is used in common BufferedRenderPipe logic so we need to implement JNI path for Metal.

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Commit messages:
 - 8254879: Implement JNI path for Draw Poly

Changes: https://git.openjdk.java.net/lanai/pull/117/files
 Webrev: https://webrevs.openjdk.java.net/?repo=lanai&pr=117&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254879
  Stats: 23 lines in 1 file changed: 21 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/lanai/pull/117.diff
  Fetch: git fetch https://git.openjdk.java.net/lanai pull/117/head:pull/117

PR: https://git.openjdk.java.net/lanai/pull/117