Reduce DexCache field/method array size to 512.

No significant change in interpreter benchmarks on Golem.
Reduces the maximum size of each of these arrays from
8KiB/16KiB to 4KiB/8KiB for 32-/64-bit architectures.

Test: Rely on TreeHugger.
Change-Id: I78833b82a672453abc4fffc6be1022b4afd7c784
diff --git a/runtime/mirror/dex_cache.h b/runtime/mirror/dex_cache.h
index ab5fb85..87f4f0a 100644
--- a/runtime/mirror/dex_cache.h
+++ b/runtime/mirror/dex_cache.h
@@ -157,12 +157,12 @@
                 "String dex cache size is not a power of 2.");
 
   // Size of field dex cache. Needs to be a power of 2 for entrypoint assumptions to hold.
-  static constexpr size_t kDexCacheFieldCacheSize = 1024;
+  static constexpr size_t kDexCacheFieldCacheSize = 512;
   static_assert(IsPowerOfTwo(kDexCacheFieldCacheSize),
                 "Field dex cache size is not a power of 2.");
 
   // Size of method dex cache. Needs to be a power of 2 for entrypoint assumptions to hold.
-  static constexpr size_t kDexCacheMethodCacheSize = 1024;
+  static constexpr size_t kDexCacheMethodCacheSize = 512;
   static_assert(IsPowerOfTwo(kDexCacheMethodCacheSize),
                 "Method dex cache size is not a power of 2.");