Interop source generators and analyzers should use HashCode.Combine to implement GetHashCode

[jtschuster]

Overrides of GetHashCode that try to combine the hash codes of fields/properties should use HashCode.Combine() instead of custom implementations.

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Issue Details

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Overrides of GetHashCode that try to combine the hash codes of fields/properties should use HashCode.Combine() instead of the custom implementations that are used currently. HashCode doesn't exist in the framework libraries in netstandard2.0, but there is a nuget package that provides the same functionality.

https://www.nuget.org/packages/Microsoft.Bcl.HashCode

Author:	jtschuster
Assignees:	jtschuster
Labels:	area-System.Runtime.InteropServices
Milestone:	-