Fix the bindhandle tests to use the correct interop description for calling CreateFile

[davidwrighton]

• The Atts and Template parameters are actually pointers, and the existing prototypes were only passing 32bit integers

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[Copilot]

Pull request overview

This PR fixes incorrect P/Invoke declarations for the Windows CreateFile API in three bindhandle test files. The 4th and 7th parameters (security attributes and template file handle) are pointer types in the native API and must be declared as pointer-sized types in the managed signature.

Changes:

• Updated CreateFile P/Invoke declarations to use nint instead of int for pointer parameters
• Ensures proper interop behavior on 64-bit systems where pointers are 64 bits

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/tests/baseservices/threading/threadpool/bindhandle/bindhandleinvalid6.cs	Fixed CreateFile P/Invoke signature to use nint for Atts and Template parameters
src/tests/baseservices/threading/threadpool/bindhandle/bindhandleinvalid3.cs	Fixed CreateFile P/Invoke signature to use nint for Atts and Template parameters
src/tests/baseservices/threading/threadpool/bindhandle/bindhandle1.cs	Fixed CreateFile P/Invoke signature to use nint for Atts and Template parameters

[AaronRobinsonMSFT]

Boo