Add the "time" compilation filter and output compilation stats.

A "time" compiler filter means the compiler optimizes for
compile time.

Change-Id: Id1a207ceb2d95f3548aae5e45d51b80695da2029
diff --git a/compiler/driver/compiler_options.h b/compiler/driver/compiler_options.h
index c0f91d1..eb3de97 100644
--- a/compiler/driver/compiler_options.h
+++ b/compiler/driver/compiler_options.h
@@ -27,7 +27,8 @@
     kSpace,               // Maximize space savings.
     kBalanced,            // Try to get the best performance return on compilation investment.
     kSpeed,               // Maximize runtime performance.
-    kEverything           // Force compilation (Note: excludes compilaton of class initializers).
+    kEverything,          // Force compilation (Note: excludes compilation of class initializers).
+    kTime                 // Compile methods, but minimize compilation time.
   };
 
   // Guide heuristics to determine whether to compile method if profile data not available.