debug/dwarf: better error message when reading absent debug_line_str
When a DW_FORM_line_strp is used without a debug_line_str section a
good error message (about the missing section) is generated but
immediately overwritten by the underflow error generated by trying to
read the non-existent section.
Updates #49590
Change-Id: I1c431392123a86c78c95ef1f185ebd6f17f2476a
Reviewed-on: https://go-review.googlesource.com/c/go/+/363894
Run-TryBot: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Trust: David Chase <drchase@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>