arch/sim: enable heap management support on simulation platform

[Shanks0224]

Summary

The simulation platform previously used a custom heap implementation that
lacked support for standard memory management features. This prevented
the use of shared memory mechanisms and consistent heap
debugging across platforms.

This patch migrates arch/sim to use the standard umm_heap framework while
maintaining necessary platform-specific customizations. The changes enable:

1. Standard heap management with shared memory support
2. Accurate memory statistics through timely delayed free processing
3. Extensible procfs interface for memory debugging
4. Proper accounting of heap metadata

Similar implementations exist in other platforms which use the umm_heap framework
with platform-specific hooks.

Impact

• Users: Enables shared memory features (OpenAMP) on simulation platform
• Build: No impact on build process; changes are conditional
• Compatibility: Maintains backward compatibility with existing sim code
• Security: No security impact; heap management internal to kernel

Testing

Host: Ubuntu 22.04 x86_64
Toolchain: gcc 11.4.0
Configuration: sim:nsh with MM_UMM_CUSTOMIZE_MANAGER enabled

Custom application testing

Created a test application (hello) to verify heap functionality:

Source Code

/****************************************************************************
 * apps/examples/hello/hello_main.c
 ****************************************************************************/

#include <nuttx/config.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, FAR char *argv[])
{
  printf("Hello, World!!!\n");
  char *p = (char *)malloc(100);
  p[50] = 'a';
  printf("p[50] = %c\n", p[50]);
  printf("p = %p\n", p);
  free(p);
  return 0;
}

Build and Run

cmake -B build_sim -DBOARD_CONFIG=boards/sim/sim/sim/configs/nsh -GNinja
cmake --build build_sim
gdb-multiarch build_sim/nuttx

Output

nsh> hello
Hello, World!!!
p[50] = a
p = 0x401bcdf0
nsh>

Results

✅ malloc(100) returns valid pointer 0x401bcdf0
✅ Memory write p[50] = 'a' succeeds
✅ Memory read outputs correct value a
✅ free(p) executes without crash
✅ Application exits cleanly

[acassis]

@Shanks0224 it is a good practice to separate logic implementation from board support. @xiaoxiang781216 please take a look

[Shanks0224]

@GUIDINGLI PTAL

[xiaoxiang781216]

@Shanks0224 remove merge patch from pr