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/gc/accounting/atomic_stack.h b/runtime/gc/accounting/atomic_stack.h
index 399832a..ac716ea 100644
--- a/runtime/gc/accounting/atomic_stack.h
+++ b/runtime/gc/accounting/atomic_stack.h
@@ -22,11 +22,11 @@
 #include <string>
 
 #include "atomic.h"
+#include "base/bit_utils.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "mem_map.h"
 #include "stack.h"
-#include "utils.h"
 
 namespace art {
 namespace gc {
diff --git a/runtime/gc/accounting/bitmap-inl.h b/runtime/gc/accounting/bitmap-inl.h
index e87a0c0..cd3923a 100644
--- a/runtime/gc/accounting/bitmap-inl.h
+++ b/runtime/gc/accounting/bitmap-inl.h
@@ -22,8 +22,8 @@
 #include <memory>
 
 #include "atomic.h"
+#include "base/bit_utils.h"
 #include "base/logging.h"
-#include "utils.h"
 
 namespace art {
 namespace gc {
diff --git a/runtime/gc/accounting/bitmap.cc b/runtime/gc/accounting/bitmap.cc
index 13fcdb3..fdded02 100644
--- a/runtime/gc/accounting/bitmap.cc
+++ b/runtime/gc/accounting/bitmap.cc
@@ -16,6 +16,7 @@
 
 #include "bitmap-inl.h"
 
+#include "base/bit_utils.h"
 #include "card_table.h"
 #include "mem_map.h"
 
diff --git a/runtime/gc/accounting/card_table-inl.h b/runtime/gc/accounting/card_table-inl.h
index b936d93..f72f219 100644
--- a/runtime/gc/accounting/card_table-inl.h
+++ b/runtime/gc/accounting/card_table-inl.h
@@ -18,11 +18,11 @@
 #define ART_RUNTIME_GC_ACCOUNTING_CARD_TABLE_INL_H_
 
 #include "atomic.h"
+#include "base/bit_utils.h"
 #include "base/logging.h"
 #include "card_table.h"
 #include "mem_map.h"
 #include "space_bitmap.h"
-#include "utils.h"
 
 namespace art {
 namespace gc {
diff --git a/runtime/gc/accounting/read_barrier_table.h b/runtime/gc/accounting/read_barrier_table.h
index bb9aae7..436df92 100644
--- a/runtime/gc/accounting/read_barrier_table.h
+++ b/runtime/gc/accounting/read_barrier_table.h
@@ -17,6 +17,7 @@
 #ifndef ART_RUNTIME_GC_ACCOUNTING_READ_BARRIER_TABLE_H_
 #define ART_RUNTIME_GC_ACCOUNTING_READ_BARRIER_TABLE_H_
 
+#include "base/bit_utils.h"
 #include "base/mutex.h"
 #include "gc/space/space.h"
 #include "globals.h"
diff --git a/runtime/gc/accounting/space_bitmap-inl.h b/runtime/gc/accounting/space_bitmap-inl.h
index ae91200..c16f5d3 100644
--- a/runtime/gc/accounting/space_bitmap-inl.h
+++ b/runtime/gc/accounting/space_bitmap-inl.h
@@ -22,8 +22,8 @@
 #include <memory>
 
 #include "atomic.h"
+#include "base/bit_utils.h"
 #include "base/logging.h"
-#include "utils.h"
 
 namespace art {
 namespace gc {