[illink] Use of DataContract attribute in Java.Lang.Object

[radekdoulik]

This pulls in System.Runtime.Serialization.Primitives assembly.

linker analyzer output:

Loading dependency tree from: bin\TestDebug\temp\BuildReleaseArm64False-net5\obj\Release\android.21-arm64\linked\linker-dependencies.xml.gz

--- Raw dependencies: 'System.Runtime.Serialization.Primitives' --------

--- Module:System.Runtime.Serialization.Primitives.dll dependencies ----
Dependency #1
        Module:System.Runtime.Serialization.Primitives.dll
        | TypeDef:System.Runtime.Serialization.DataContractAttribute [1 deps]
        | Method:System.Void System.Runtime.Serialization.DataContractAttribute::.ctor()

History context:
https://github.com/xamarin/monodroid/commit/8666bf93d15c51438b09b35b1f0d5d638307ae4e
https://github.com/xamarin/monodroid/commit/28e00eda2dc20bc23371e17f2f8c208864788be7

Let see if we can remove it.

[radekdoulik]

Done.

#5473