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/malloc_debug_common.h

@@ -45,6 +45,11 @@
 
 #define MAX_SIZE_T           (~(size_t)0)
 
+// This must match the alignment used by dlmalloc.
+#ifndef MALLOC_ALIGNMENT
+#define MALLOC_ALIGNMENT ((size_t)(2 * sizeof(void *)))
+#endif
+
 // =============================================================================
 // Structures
 // =============================================================================
@@ -71,12 +76,14 @@ typedef void (*MallocDebugFree)(void*);
 typedef void* (*MallocDebugCalloc)(size_t, size_t);
 typedef void* (*MallocDebugRealloc)(void*, size_t);
 typedef void* (*MallocDebugMemalign)(size_t, size_t);
+typedef size_t (*MallocDebugMallocUsableSize)(const void*);
 struct MallocDebug {
   MallocDebugMalloc malloc;
   MallocDebugFree free;
   MallocDebugCalloc calloc;
   MallocDebugRealloc realloc;
   MallocDebugMemalign memalign;
+  MallocDebugMallocUsableSize malloc_usable_size;
 };
 
 /* Malloc debugging initialization and finalization routines.