Implement malloc_usable_size for debug impls.

- Implemented chk_memalign.
- Fixed a few bugs in leak_memalign.
- Implemented {leak,fill,check,qemu}_malloc_usable_size.
- Make malloc_usable_size update at run time.
- Add malloc_test.cpp as a small set of tests for the
  malloc debug routines.
- Fix the qemu routines since it's been broken since it moved to C++.
- Add support for the %u format to the out_vformat in libc_logging.cpp.
  This is used by the emulator code.

Tested using the bionic-unit-tests with setprop libc.debug.malloc
set to 1, 5, and 10.

I tested as much as possible on the emulator, but tracing doesn't appear
to be working properly.

Bug: 6143477

Merge change from internal master.

(cherry-picked from commit 3d594c2580)

Change-Id: I4ae00fffba82315a8c283f35893fd554460722fb

libc/bionic/libc_logging.cpp

@@ -348,7 +348,7 @@ static void out_vformat(Out& o, const char* format, va_list args) {
             buffer[0] = '0';
             buffer[1] = 'x';
             format_integer(buffer + 2, sizeof(buffer) - 2, value, 'x');
-        } else if (c == 'd' || c == 'i' || c == 'o' || c == 'x' || c == 'X') {
+        } else if (c == 'd' || c == 'i' || c == 'o' || c == 'u' || c == 'x' || c == 'X') {
             /* integers - first read value from stack */
             uint64_t value;
             int is_signed = (c == 'd' || c == 'i' || c == 'o');