Fix the paths at which CompileContext locates resgen outputs.

Fixes #1136

TestAssets/TestProjects/TestProjectWithResource/Program.cs

@@ -0,0 +1,18 @@
+using System;
+using System.Resources;
+using System.Reflection;
+
+namespace TestProjectWithResource
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            var rm = new ResourceManager(
+                "TestProjectWithResource.Strings",
+                typeof(Program).GetTypeInfo().Assembly);
+
+            Console.WriteLine(rm.GetString("hello"));
+        }
+    }
+}