Draft: iris: Use BLORP_BATCH_NO_EMIT_DEPTH_STENCIL
Don't emit depth-stencil packets when a BLORP call uses NULL depth-stencil buffers and the last submitted depth-stencil buffers are NULL.
Commit 34dbbfdd introduced additional stalling when depth-stencil packets are emitted for BLORP calls on TGL. This caused iris to perform worse while running the SynMark2 OglHdrBloom benchmark on TGL.
By avoiding redundant NULL depth-stencil packet emission, the performance regression is fixed. Compared to commit 75a9cb10, this improves the driver's performance on that benchmark by 9.31% ±0.07% (n=2) on TGL.
Edited by Nanley Chery