Add optimization for scalar/vector conversion of `uint32`/`uint64` to/from packed `float`/`double`

[anthonycanino]

AVX512VL adds a number of new scalar/packed conversion for unsigned 32-bit/64-bit integer types to float/double. These allow to replace less efficient conversions on xarch --- either multiple instructions or dedicated helper methods --- with single accelerated instructions.

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Issue Details

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AVX512VL adds a number of new scalar/packed conversion for unsigned 32-bit/64-bit integer types to float/double. These allow to replace less efficient conversions on xarch --- either multiple instructions or dedicated helper methods --- with single accelerated instructions.

Author:	anthonycanino
Assignees:	-
Labels:	area-CodeGen-coreclr, arch-avx512
Milestone:	-