Increase GC card size to 1024

With CC, having a larger GC card size does not commonly affect
pauses.

Results:
Before (128):
System wide card table PSS: 3642.4K
GrayAllNewlyDirtyImmuneObjects avg: 145us

After (1024):
System wide card table PSS: 1477.8K
GrayAllNewlyDirtyImmuneObjects avg: 75us

Test: test-art-host

Bug: 36457259
Change-Id: Icec03664985ef75859f4e99d9f76c3b9988193e6
diff --git a/runtime/gc/space/image_space.cc b/runtime/gc/space/image_space.cc
index e9f0758..238e87e 100644
--- a/runtime/gc/space/image_space.cc
+++ b/runtime/gc/space/image_space.cc
@@ -651,7 +651,8 @@
               bitmap_name,
               image_bitmap_map.release(),
               reinterpret_cast<uint8_t*>(map->Begin()),
-              image_objects.End()));
+              // Make sure the bitmap is aligned to card size instead of just bitmap word size.
+              RoundUp(image_objects.End(), gc::accounting::CardTable::kCardSize)));
       if (bitmap == nullptr) {
         *error_msg = StringPrintf("Could not create bitmap '%s'", bitmap_name.c_str());
         return nullptr;