perf dwarf-aux: Preserve typedefs in match_var_offset

perf dwarf-aux: Preserve typedefs in match_var_offset

Preserve typedefs in match_var_offset to match the results by
__die_get_real_type. Also move the (offset == 0) branch after the
is_pointer check to ensure the correct type is used, fixing cases where
an incorrect pointer type was chosen when the access offset was 0.

Signed-off-by: Zecheng Li <zecheng@google.com>
Signed-off-by: Zecheng Li <zli94@ncsu.edu>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>