COFF objects in particular don't contain the size of
symbols. We infer the size of these symbols by
extending them to the next symbol. If a tool emits
symbols for branch targets, this causes the inferred
size to be too small.
This checks if a symbol starts with a certain prefix
(right now, just .L or LAB_), and skips over it
during symbol size inference.
Resolves#174
Before, this was comparing, for example, `.text-2`
with `.text-10` with standard string comparison,
yielding `.text-10` before `.text-2`.
Instead, this simply uses a stable sort by name,
which preserves the relative ordering of sections.
