Bump xDiT stack

[lauri9]

Bump xDiT, transformers, diffusers, and DistVAE.

Closes #1001

Background

Bump xDiT to support MHAv4 dense and sparse backends.

Diffusers bump is needed to support new LTX2.5 API in xDiT. Transformers bump is needed to support the new diffusers version. DistVAE is bumped to meet xDiT requirements (now need DistVAE>=0.1.0).

Goals

• Bump xDiT stack, adding support for MHAv4 attention kernels

Tasks

• Bump SW stack
• Verify performance and visual quality

Tests

CI run here.

Visually all outputs look good. Performance was tested compared to last AITER bump.

MI350X performance

model	xDiT bump	AITER 4ce24d1	Ratio
flux.usp	0.78	0.84	108.2%
flux.single_gpu	2.35	2.38	101.4%
flux.usp_2k	2.17	2.22	102.3%
flux.single_gpu_2k	11.88	12.01	101.0%
flux2.default	4.39	4.44	101.1%
flux2.quantgemm.gfx950	2.36	2.44	103.3%
flux2.quantgemm_sageattn.gfx950	2.49	2.57	103.3%
flux2.ti2i_2k	12.38	12.57	101.5%
flux2.t2i_1k	2.84	2.87	101.0%
flux2.t2i_2k	10.55	10.74	101.8%
flux2.t-multi-i2i_1k	5.87	5.95	101.4%
flux2.t-multi-i2i_2k	14.83	15.05	101.4%
flux2_klein.default	0.48	0.48	100.2%
flux_kontext.default	1.45	1.50	103.3%
hunyuanvideo.default	104.76	104.82	100.1%
hunyuanvideo.fp8attn	63.68	65.16	102.3%
hunyuanvideo.sageattn.gfx950	87.72	87.52	99.8%
hunyuanvideo_1_5.default	115.92	115.67	99.8%
ltx2_3.default	15.97	16.06	100.5%
qwen_image.default	4.75	4.81	101.3%
qwen_image_edit.default	14.81	15.07	101.8%
stablediffusion_3_5.default	0.82	0.81	99.3%
wan2_1.default	74.03	73.15	98.8%
wan2_2.default	75.89	75.21	99.1%
wan2_2.quantgemm.gfx950	67.31	67.25	99.9%
wan2_2.quantgemm_fp8attn.gfx950	39.09	40.50	103.6%
wan2_2.quantgemm_sageattn.gfx950	52.99	53.04	100.1%
wan2_2.quantgemm_spargeattn.gfx950	30.48	30.59	100.4%
z_image.default	2.56	2.64	103.2%

MI300X performance. These configs were rerun manually due to transient issues on CI: flux.usp, flux.single_gpu, flux2.quantgemm.gfx942, flux2.quantgemm_sageattn.gfx942, hunyuanvideo.default

model	xDiT bump	AITER 4ce24d1	Ratio
flux.usp	1.21	1.28	105.7%
flux.single_gpu	3.78	3.79	100.4%
flux.usp_2k	3.82	3.78	99.1%
flux.single_gpu_2k	20.09	20.10	100.0%
flux2.default	7.70	7.69	99.9%
flux2.quantgemm.gfx942	5.36	5.52	103.1%
flux2.quantgemm_sageattn.gfx942	5.63	5.73	101.8%
flux2.ti2i_2k	22.53	22.58	100.2%
flux2.t2i_1k	5.04	5.05	100.2%
flux2.t2i_2k	18.51	18.59	100.4%
flux2.t-multi-i2i_1k	9.86	10.00	101.4%
flux2.t-multi-i2i_2k	25.35	25.64	101.1%
flux2_klein.default	0.78	0.79	101.4%
flux_kontext.default	2.40	2.45	102.2%
hunyuanvideo.default	178.01	176.50	99.2%
hunyuanvideo.fp8attn	118.22	129.46	109.5%
hunyuanvideo.sageattn.gfx942	147.90	148.18	100.2%
hunyuanvideo_1_5.default	219.06	219.14	100.0%
ltx2_3.default	27.31	27.07	99.1%
qwen_image.default	8.03	8.19	101.9%
qwen_image_edit.default	22.07	22.72	103.0%
stablediffusion_3_5.default	1.26	1.25	99.3%
wan2_1.default	133.41	133.72	100.2%
wan2_2.default	133.20	133.32	100.1%
wan2_2.quantgemm.gfx942	120.52	121.03	100.4%
wan2_2.quantgemm_fp8attn.gfx942	76.97	88.04	114.4%
wan2_2.quantgemm_sageattn.gfx942	99.30	99.53	100.2%
wan2_2.quantgemm_spargeattn.gfx942	73.01	73.81	101.1%
z_image.default	4.37	4.53	103.7%

Other

n/a