`JUNK_xxxx` label must not become `LABEL_xxxx` if junk code references its address

[felipesanches]

Here's an example from msdos bytecode (level_2):

Address 0x0480 is never called. But its code has a JMP pointing to its own entry point at 0x0480. For that reason the disassembler ended up using the label LABEL_0480 instead of the expected JUNK_0480. For that reason, it becomes unclear that that snipped of disassembly is an unused piece of code.