perf dwarf-aux: Collect all variable locations for insn tracking

perf dwarf-aux: Collect all variable locations for insn tracking

Previously, only the first DWARF location entry was collected for each
variable. This was based on the assumption that instruction tracking
could reconstruct the remaining state. However, variables may have
different locations across different address ranges, and relying solely
on instruction tracking can miss valid type information.

Change __die_collect_vars_cb() to iterate over all location entries
using dwarf_getlocations() in a loop. This ensures that variables with
multiple location ranges are properly tracked, improving type coverage.

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