[pkg/winperfcounters] Fix -race test failures due to checkptr violations

[BinaryFissionGames]

Description:

• Avoid using the custom UTF16ToStringArray function if syscall.UTF16ToString would work just fine.
• Avoid casting pointers to large arrays in the winperfcounters package
  • The go race detector will error with checkptr: converted pointer straddles multiple allocations otherwise

Link to tracking Issue:

• Resolves [pkg/winperfcounters] Tests are failing with -race check #10145
• Resolves [receiver/iis] Tests are failing with -race check #10146
• Resolves [receiver/sqlserver] Tests are failing with -race check #10149
• Resolves [receiver/windowsperfcounters] Tests are failing with -race check #10150

Testing:

• Remove make options disabling -race flag
• Unit tests for affected functions

[BinaryFissionGames]

cc @dmitryax

[dmitryax]

@BinaryFissionGames thanks for fixing this!