[Java.Intreop] Rename Dispose methods

These have different signatures than the common dispose pattern
methods, thus rename them to avoid confusion.

Catched by gendarme's
https://github.com/spouliot/gendarme/wiki/Gendarme.Rules.Design.UseCorrectDisposeSignaturesRule(2.10)

src/Java.Interop/Java.Interop/JavaException.cs

@@ -153,7 +153,7 @@ public void UnregisterFromRuntime ()
 
 		public void Dispose ()
 		{
-			JniEnvironment.Runtime.ValueManager.Dispose (this);
+			JniEnvironment.Runtime.ValueManager.DisposePeer (this);
 		}
 
 		public void DisposeUnlessReferenced ()

src/Java.Interop/Java.Interop/JavaObject.cs

@@ -105,7 +105,7 @@ public void UnregisterFromRuntime ()
 
 		public void Dispose ()
 		{
-			JniEnvironment.Runtime.ValueManager.Dispose (this);
+			JniEnvironment.Runtime.ValueManager.DisposePeer (this);
 		}
 
 		public void DisposeUnlessReferenced ()

src/Java.Interop/Java.Interop/JniRuntime.JniValueManager.cs

@@ -121,7 +121,7 @@ public int GetJniIdentityHashCode (JniObjectReference reference)
 				return JniSystem.IdentityHashCode (reference);
 			}
 
-			public virtual void Dispose (IJavaPeerable value)
+			public virtual void DisposePeer (IJavaPeerable value)
 			{
 				if (value == null)
 					throw new ArgumentNullException (nameof (value));
@@ -130,10 +130,10 @@ public virtual void Dispose (IJavaPeerable value)
 				if (!h.IsValid)
 					return;
 
-				Dispose (h, value);
+				DisposePeer (h, value);
 			}
 
-			void Dispose (JniObjectReference h, IJavaPeerable value)
+			void DisposePeer (JniObjectReference h, IJavaPeerable value)
 			{
 				value.Disposed ();
 				Remove (value);
@@ -173,7 +173,7 @@ public virtual void DisposeUnlessReferenced (IJavaPeerable value)
 				if (o != null && object.ReferenceEquals (o, value))
 					return;
 
-				Dispose (h, value);
+				DisposePeer (h, value);
 			}
 
 			public abstract IJavaPeerable PeekPeer (JniObjectReference reference);