[jnimarshalmethod-gen] Use ReaderParameters.InMemory=true (dotnet#369)

Set `ReaderParameters.InMemory=true` so that assemblies are loaded
into memory for processing, instead of reading their contents lazily
from disk.  This helps to process the assembly faster

Times when processing `Mono.Android.dll`:

Before:

	All         37.34 real        37.29 user         2.04 sys
	Limited      7.02 real         6.54 user         1.17 sys

After:

	All         33.84 real        34.99 user         1.01 sys
	Limited      4.41 real         4.76 user         0.36 sys

Where *All* has `jnimarshalmethod-gen.exe` processing *all* types in
the assembly, while *Limited* means to use
`jnimarshalmethod-gen.exe --types=FILE` where `FILE` contains the
following listed types:

	# XA template startup, Mono.Android
	#
	Android.Runtime.UncaughtExceptionHandler
	Java.Interop.TypeManager\+JavaTypeManager
	Android.Views.View\+IOnClickListenerImplementor

	# XForms template, Mono.Android
	#
	Android.Animation.ValueAnimator\+IAnimatorUpdateListenerImplementor
	Java.Lang.Thread\+RunnableImplementor

Author: radekdoulik

tools/jnimarshalmethod-gen/App.cs

@@ -19,7 +19,7 @@ class App : MarshalByRefObject
 	{
 
 		internal const string Name = "jnimarshalmethod-gen";
-		static DirectoryAssemblyResolver resolver = new DirectoryAssemblyResolver (logger: (l, v) => { Console.WriteLine (v); }, loadDebugSymbols: true, loadReaderParameters: new ReaderParameters () { ReadSymbols = true });
+		static DirectoryAssemblyResolver resolver = new DirectoryAssemblyResolver (logger: (l, v) => { Console.WriteLine (v); }, loadDebugSymbols: true, loadReaderParameters: new ReaderParameters () { ReadSymbols = true, InMemory = true });
 		static Dictionary<string, TypeBuilder> definedTypes = new Dictionary<string, TypeBuilder> ();
 		static Dictionary<string, TypeDefinition> typeMap = new Dictionary<string, TypeDefinition> ();
 		static public bool Debug;
@@ -145,11 +145,13 @@ void ProcessAssemblies (List<string> assemblies)
 
 			var readWriteParameters    = new ReaderParameters {
 				AssemblyResolver   = resolver,
+				InMemory           = true,
 				ReadSymbols        = true,
 				ReadWrite          = true,
 			};
 			var readWriteParametersNoSymbols    = new ReaderParameters {
 				AssemblyResolver   = resolver,
+				InMemory           = true,
 				ReadSymbols        = false,
 				ReadWrite          = true,
 			};
@@ -347,7 +349,7 @@ void CreateMarshalMethodAssembly (string path)
 				ColorWriteLine ($"Marshal method assembly '{assemblyName}' created", ConsoleColor.Cyan);
 
 			var dstAssembly = resolver.GetAssembly (destPath);
-			var mover = new TypeMover (dstAssembly, ad, definedTypes, resolver);
+			var mover = new TypeMover (dstAssembly, ad, path, definedTypes, resolver);
 			mover.Move ();
 
 			if (!keepTemporary)

tools/jnimarshalmethod-gen/TypeMover.cs

@@ -13,14 +13,16 @@ public class TypeMover
 	{
 		AssemblyDefinition Source { get; }
 		AssemblyDefinition Destination { get; }
+		string DestinationPath { get; }
 		Dictionary<string, System.Reflection.Emit.TypeBuilder> Types { get; }
 
 		MethodReference consoleWriteLine;
 
-		public TypeMover (AssemblyDefinition source, AssemblyDefinition destination, Dictionary<string, System.Reflection.Emit.TypeBuilder> types, DirectoryAssemblyResolver resolver)
+		public TypeMover (AssemblyDefinition source, AssemblyDefinition destination, string destinationPath, Dictionary<string, System.Reflection.Emit.TypeBuilder> types, DirectoryAssemblyResolver resolver)
 		{
 			Source = source;
 			Destination = destination;
+			DestinationPath = destinationPath;
 			Types = types;
 
 			if (App.Debug) {
@@ -49,7 +51,7 @@ public void Move ()
 				return;
 			}
 
-			Destination.Write (new WriterParameters () { WriteSymbols = Destination.MainModule.HasSymbols });
+			Destination.Write (DestinationPath, new WriterParameters () { WriteSymbols = Destination.MainModule.HasSymbols });
 
 			if (App.Verbose)
 				App.ColorWriteLine ($"Wrote updated {Destination.MainModule.FileName} assembly", ConsoleColor.Cyan);