Add hexdump to trailing user data for vis_heap_chunks command (#2620)

pwndbg/commands/ptmalloc2.py

@@ -1135,6 +1135,11 @@ def vis_heap_chunks(
 
             cursor += ptr_size
 
+    if printed % 2 != 0:
+        # Alignment whitespace of ("0x" + "00" * ptr_size) length.
+        machine_word_string_length = 2 + (2 * ptr_size)
+        out += "\t" + " " * machine_word_string_length + "\t" + color_func(asc)
+
     print(out)
 
     if reached_mapping_end:

tests/gdb-tests/tests/heap/test_vis_heap_chunks.py

@@ -69,7 +69,7 @@ def test_vis_heap_chunk_command(start_binary):
         expected.append(
             "%#x\t0x0000000000000000\t0x0000000000000000\t................" % heap_iter()
         )
-    expected.append("%#x\t0x0000000000000000" % heap_iter())
+    expected.append("%#x\t0x0000000000000000\t                  \t........" % heap_iter())
     assert result == expected
 
     ## This time using `default-visualize-chunk-number` to set `count`, to make sure that the config can work
@@ -92,7 +92,7 @@ def test_vis_heap_chunk_command(start_binary):
     expected2 = expected[:-1] + [
         "%#x\t0x0000000000000000\t0x0000000000000021\t........!......." % heap_iter(0),
         "%#x\t0x0000000000000000\t0x0000000000000000\t................" % heap_iter(),
-        "%#x\t0x0000000000000000" % heap_iter(),
+        "%#x\t0x0000000000000000\t                  \t........" % heap_iter(),
     ]
     assert result2 == expected2