ART: Clean up arm64 kNumberOfXRegisters usage.

Avoid undefined behavior for arm64 stemming from 1u << 32 in
loops with upper bound kNumberOfXRegisters.

Create iterators for enumerating bits in an integer either
from high to low or from low to high and use them for
<arch>Context::FillCalleeSaves() on all architectures.

Refactor runtime/utils.{h,cc} by moving all bit-fiddling
functions to runtime/base/bit_utils.{h,cc} (together with
the new bit iterators) and all time-related functions to
runtime/base/time_utils.{h,cc}. Improve test coverage and
fix some corner cases for the bit-fiddling functions.

Bug: 13925192
Change-Id: I704884dab15b41ecf7a1c47d397ab1c3fc7ee0f7
diff --git a/runtime/native/dalvik_system_VMDebug.cc b/runtime/native/dalvik_system_VMDebug.cc
index 46881b0..1078492 100644
--- a/runtime/native/dalvik_system_VMDebug.cc
+++ b/runtime/native/dalvik_system_VMDebug.cc
@@ -22,6 +22,7 @@
 #include <sstream>
 
 #include "base/histogram-inl.h"
+#include "base/time_utils.h"
 #include "class_linker.h"
 #include "common_throws.h"
 #include "debugger.h"
diff --git a/runtime/native/java_lang_reflect_Field.cc b/runtime/native/java_lang_reflect_Field.cc
index 721b7a3..d6aa9b5 100644
--- a/runtime/native/java_lang_reflect_Field.cc
+++ b/runtime/native/java_lang_reflect_Field.cc
@@ -26,6 +26,7 @@
 #include "mirror/field.h"
 #include "reflection-inl.h"
 #include "scoped_fast_native_object_access.h"
+#include "utils.h"
 
 namespace art {