[illink] Use of ConcurrentDictionary`2

[radekdoulik]

Check whether we really need it. It pulls in System.Collections.Concurrent assembly.

part of linker analyzer output:

--- Module:System.Collections.Concurrent.dll dependencies --------------
Dependency #1
        Module:System.Collections.Concurrent.dll
        | TypeDef:System.Collections.Concurrent.ConcurrentDictionary`2 [40 deps]
        | TypeSpec:System.Collections.Concurrent.ConcurrentDictionary`2<System.IntPtr,System.IDisposable> [6 deps]
        | MemberRef:System.Void System.Collections.Concurrent.ConcurrentDictionary`2<System.IntPtr,System.IDisposable>::.ctor() [1 deps]
        | Method:System.Void Java.Interop.JniRuntime::.ctor(Java.Interop.JniRuntime/CreationOptions) [2 deps]
        | Method:System.Void Android.Runtime.AndroidRuntime::.ctor(System.IntPtr,System.IntPtr,System.Boolean,System.IntPtr,System.IntPtr,System.Boolean) [1 deps]
        | Method:System.Void Android.Runtime.JNIEnv::Initialize(Android.Runtime.JnienvInitializeArgs*) [1 deps]
        | Other:C:\Users\rodo\android-toolchain\dotnet\packs\Microsoft.Android.Sdk.win-x64\11.0.100-ci.master.317\targets\..\PreserveLists\Mono.Android.xml

[jonpryor]

No, we don't need it. We can use lock instead.

[radekdoulik]

Cool, I will take a look at it.

[radekdoulik]

Done.

dotnet/java-interop#791
#5598