Fix chunk listing with tcache

[x0urc3]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've added tests that prove my fix is effective or that my feature works (if possible)
• I've updated the documentation and the radare2 book with the relevant information (if needed)

Detailed description

• dmh was broken because it uses a hardcoded offset from dbg.glibc.fc_offset
• This PR use tcache chunk size to find the next chunk
• Please do not close yet. There are several other places that uses fc_offset that I would like to fix in this PR

$ grep -IR fc_offset libr/*
libr/core/cconfig.c:    SETI ("dbg.glibc.fc_offset", 0x00240, "First chunk offset from brk_start");
libr/core/cconfig.c:    SETI ("dbg.glibc.fc_offset", 0x148, "First chunk offset from brk_start");
libr/core/linux_heap_glibc.c:           const int fc_offset = r_config_get_i (core->config, "dbg.glibc.fc_offset");
libr/core/linux_heap_glibc.c:           initial_brk = ( (brk_start >> 12) << 12 ) + fc_offset;
libr/core/linux_heap_glibc.c:   const int offset = r_config_get_i (core->config, "dbg.glibc.fc_offset");
libr/core/linux_heap_glibc.c:   const int offset = r_config_get_i (core->config, "dbg.glibc.fc_offset");
libr/main/radare2.c:                                                    eprintf ("glibc.fc_offset = 0x00148\n");
libr/main/radare2.c:                                                    r_config_set_i (r->config, "dbg.glibc.fc_offset", 0x00148);

Test plan

• A test has been added to count allocated chunk. Result has been compared with gdb-gef

Closing issues

Closes #16206