[cherry-pick][release/2.13] MD-TRT: move USE_C10D_NCCL from copts to defines (#4358 BUILD)

[apbose]

Corrected cherry-pick of the core/runtime/BUILD change from #4358 onto current release/2.13, replacing the earlier PR #4374 which dropped it.

What this fixes
The BUILD portion of #4358 moves the NCCL macro from a target-local copts flag to a propagating defines:

-    copts = if_torch_nccl(["-DUSE_C10D_NCCL"]),
-    defines = select({ ...TRT_HAS_IRUNTIME_CONFIG... }),
+    defines = if_torch_nccl(["USE_C10D_NCCL"]) + select({ ...TRT_HAS_IRUNTIME_CONFIG... }),

This matters because copts applies -DUSE_C10D_NCCL only to runtime_base's own translation units, whereas defines propagates USE_C10D_NCCL to every dependent that compiles against the runtime headers — keeping the #ifdef USE_C10D_NCCL code paths consistent across the dependency graph.

Why a new PR
The original cherry-pick was resolved when release/2.13 predated the IRuntimeConfig infrastructure, and the BUILD change was dropped entirely. release/2.13 has since added RuntimeSettings.* / TRTRuntimeConfig.* and the defines = select({TRT_HAS_IRUNTIME_CONFIG}) block, so #4358's BUILD change now applies cleanly on top of it. This branch is rebuilt on current release/2.13; the only delta is the copts→defines merge — RuntimeSettings/TRTRuntimeConfig are retained, nothing dropped.

The other two files from #4358 (_utils.py, _TRTInterpreter.py) are already present on release/2.13, so they produce no delta here.

Supersedes #4374. Original PR: #4358

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