[Java.Interop.Tools.Cecil] remove System.Linq in IsSubclassOf (#577)

Using the Mono profiler, I found:

	Allocation summary
	    Bytes      Count  Average Type name
	  7636736      59662      128 System.Func<Mono.Cecil.TypeDefinition,System.Boolean>
	  3685952      57593       64 Java.Interop.Tools.Cecil.TypeDefinitionRocks.<GetTypeAndBaseTypes>d__3

The stack traces of these are from:

	2498944 bytes from:
	    Xamarin.Android.Tasks.GenerateJavaStubs:Run (Java.Interop.Tools.Cecil.DirectoryAssemblyResolver)
	    Xamarin.Android.Tasks.ManifestDocument:Merge (Microsoft.Build.Utilities.TaskLoggingHelper,Java.Interop.Tools.Cecil.TypeDefinitionCache,System.Collections.Generic.List`1<Mono.Cecil.TypeDefinition>,string,bool,string,System.Collections.Generic.IEnumerable`1<string>)
	    Xamarin.Android.Tasks.ManifestDocument:GetGenerator (Mono.Cecil.TypeDefinition,Java.Interop.Tools.Cecil.TypeDefinitionCache)
	    Java.Interop.Tools.Cecil.TypeDefinitionRocks:IsSubclassOf (Mono.Cecil.TypeDefinition,string,Java.Interop.Tools.Cecil.TypeDefinitionCache)
	    (wrapper alloc) object:ProfilerAllocSmall (intptr,intptr)
	    (wrapper managed-to-native) object:__icall_wrapper_mono_profiler_raise_gc_allocation (object)
	...
	1273344 bytes from:
	    Xamarin.Android.Tasks.ManifestDocument:Merge (Microsoft.Build.Utilities.TaskLoggingHelper,Java.Interop.Tools.Cecil.TypeDefinitionCache,System.Collections.Generic.List`1<Mono.Cecil.TypeDefinition>,string,bool,string,System.Collections.Generic.IEnumerable`1<string>)
	    Xamarin.Android.Tasks.ManifestDocument:GetGenerator (Mono.Cecil.TypeDefinition,Java.Interop.Tools.Cecil.TypeDefinitionCache)
	    Java.Interop.Tools.Cecil.TypeDefinitionRocks:IsSubclassOf (Mono.Cecil.TypeDefinition,string,Java.Interop.Tools.Cecil.TypeDefinitionCache)
	    Java.Interop.Tools.Cecil.TypeDefinitionRocks:GetTypeAndBaseTypes (Mono.Cecil.TypeDefinition,Java.Interop.Tools.Cecil.TypeDefinitionCache)
	    (wrapper alloc) object:ProfilerAllocSmall (intptr,intptr)
	    (wrapper managed-to-native) object:__icall_wrapper_mono_profiler_raise_gc_allocation (object)

This `TypeDefinitionRocks.IsSubclassOf()` method gets called ~40K
times during a build:

	Method call summary
	Total(ms) Self(ms)      Calls Method name
	     2431      117      43493 Java.Interop.Tools.Cecil.TypeDefinitionRocks:IsSubclassOf (Mono.Cecil.TypeDefinition,string,Java.Interop.Tools.Cecil.TypeDefinitionCache)

Reviewing `IsSubclassOf()` we can just remove the System.Linq usage
and use a `foreach` loop instead.

The results of building the Xamarin.Forms integration project on
Windows:

  * Before:

        559 ms  GenerateJavaStubs                          1 calls

  * After:

        535 ms  GenerateJavaStubs                          1 calls

A ~24ms savings is pretty good for a small app.

I suspect it would have even better improvements on macOS / Mono, due
to what I saw in: dotnet/android#4260

Author: jonathanpeppers

src/Java.Interop.Tools.Cecil/Java.Interop.Tools.Cecil/TypeDefinitionRocks.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 
 using Mono.Cecil;
 
@@ -74,7 +73,12 @@ public static bool IsSubclassOf (this TypeDefinition type, string typeName) =>
 
 		public static bool IsSubclassOf (this TypeDefinition type, string typeName, TypeDefinitionCache cache)
 		{
-			return type.GetTypeAndBaseTypes (cache).Any (t => t.FullName == typeName);
+			foreach (var t in type.GetTypeAndBaseTypes (cache)) {
+				if (t.FullName == typeName) {
+					return true;
+				}
+			}
+			return false;
 		}
 
 		[Obsolete ("Use the TypeDefinitionCache overload for better performance.")]