Replace "DML CPU" Allocator with onnxruntime::CpuAllocator (#21818)
### Description
Replace "DML CPU" Allocator with onnxruntime::CpuAllocator
### Motivation and Context
This allocator is being ignored by ORTExtensions and causes CPU memory
to be treated as non-CPU memory and crash in SentencepieceTokenizer.
In general it seems like this allocator is not used and can be handled
just fine by the default allocator.
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Co-authored-by: Sheil Kumar <sheilk@microsoft.com>