ART: Convert pointer size to enum

Move away from size_t to dedicated enum (class).

Bug: 30373134
Bug: 30419309
Test: m test-art-host
Change-Id: Id453c330f1065012e7d4f9fc24ac477cc9bb9269
diff --git a/runtime/Android.mk b/runtime/Android.mk
index 99c4a82..2b06671 100644
--- a/runtime/Android.mk
+++ b/runtime/Android.mk
@@ -342,6 +342,7 @@
 LIBART_ENUM_OPERATOR_OUT_HEADER_FILES := \
   arch/instruction_set.h \
   base/allocator.h \
+  base/enums.h \
   base/mutex.h \
   debugger.h \
   base/unix_file/fd_file.h \