[Mono] Intrinsify StoreSelectedScalar

[fanyang-mono]

Contributes to #93081

This PR intrinsify the following API's:

• AdvSimd.StoreSelectedScalar
• AdvSimd.Arm64.StoreSelectedScalar

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Issue Details

---

Contributes to #93081

This PR intrinsify the following API's:

• AdvSimd.StoreSelectedScalar
• AdvSimd.Arm64.StoreSelectedScalar

Author:	fanyang-mono
Assignees:	fanyang-mono
Labels:	area-System.Runtime.Intrinsics, new-api-needs-documentation
Milestone:	-

[fanyang-mono]

Runtime tests passed locally

Supported ISAs:
  AdvSimd:   True
  Aes:       True
  ArmBase:   True
  Crc32:     True
  Dp:        False
  Rdm:       False
  Sha1:      True
  Sha256:    True
  Sve:       False
......
Expected: 100
Actual: 100
END EXECUTION - PASSED

[kunalspathak]

libraries and tests changes LGTM. Thanks!

[fanyang-mono]

Failures on Build android-arm Release AllSubsets_Mono were caused by devices not found, which is unrelated to this PR.