[Determinism] torch.utils.deterministic.fill_uninitialized_memory default to false for determinism perf

**Describe the bug**

Determinism tax reduced from ~15% to ~2%, based on optimizations proposed by Nathan Tuck US

torch.utils.deterministic.fill_uninitialized_memory defaults to true with torch determinism setup but it is too strict not necessary to ensure determinism.

**Steps/Code to reproduce bug**

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A helpful guide on on how to craft a minimal bug report http://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports.

**Expected behavior**

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**Additional context**

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