[JniEnvironment] Revert change that changed an NSE to an ODE.

Author: jpobst

src/Java.Interop/Java.Interop/JniEnvironment.cs

@@ -192,7 +192,7 @@ sealed class JniEnvironmentInfo : IDisposable {
 		public      int                     LocalReferenceCount     {get; internal set;}
 		public      bool                    WithinNewObjectScope    {get; set;}
 		public      JniRuntime              Runtime {
-			get => runtime ?? throw new ObjectDisposedException (nameof (JniEnvironmentInfo));
+			get => runtime ?? throw new NotSupportedException ();
 			private set => runtime = value;
 		}
 

tests/Java.Interop-Tests/Java.Interop/JniRuntimeTest.cs

@@ -58,7 +58,7 @@ public void Dispose_ClearsJniEnvironment ()
 				JniRuntime.SetCurrent (r);
 				Assert.AreEqual (r, JniEnvironment.Runtime);
 				r.Dispose ();
-				Assert.Throws<ObjectDisposedException>(() => {
+				Assert.Throws<NotSupportedException>(() => {
 					var env = JniEnvironment.Runtime;
 				});
 			});