Add listFilesOnly command-line option

Msbuild currently uses a combination of `--listFiles` and `--noEmit` to
obtain a list of files to be consumed by tsc.  However, these two flags
don't suppress type checking, the results of which msbuild will never
consume.  This new switch gives msbuild a faster way to obtain the file
list.

Note: like `--noEmit`, doesn't make sense in build mode.

src/compiler/commandLineParser.ts

@@ -216,6 +216,13 @@ namespace ts {
             isCommandLineOnly: true,
             description: Diagnostics.Print_the_final_configuration_instead_of_building
         },
+        {
+            name: "listFilesOnly",
+            type: "boolean",
+            category: Diagnostics.Command_line_Options,
+            isCommandLineOnly: true,
+            description: Diagnostics.Print_names_of_files_that_are_part_of_the_compilation_and_then_stop_processing
+        },
 
         // Basic
         {