[RCCL] Fix p2p_batching, revert PR 3001, disable warpSpeed on gfx942

[isaki001]

Motivation

Resolve errors/regressions

Technical Details

• Restore p2p-batching functionality that was broken with NCCL sync.
• revert PR 3001 due to regression on all collectives
• disable warpSpeed building for gfx942, to resolve regressions. warpSpeed is still not enabled by default on MI300 but building added non-negligible overhead.

JIRA ID

Test Plan

Evaluate correctness and performance by running 1N/2N/4N/8N/16N allReduce, allGather, reduceScatter, and alltoall on gfx942 and gfx950.

Test Result

Fixed errors when enabling p2p-batching
Improved perf. on gfx942 and gfx950

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.