Add linting checks for DWARF unwind information

DWARF unwind information is rather subtle and needs to be manually specified in some cases. Having at least some basic sanity checks would hep prevent against things like #14999 (closed).

Trac metadata

Trac field	Value
Version	8.2.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	niteria
Operating system
Architecture

mentioned in issue #14999 (closed)

changed milestone to %8.6.1

changed weight to 5

added Tbug Trac import labels

Trac metadata

Trac field	Value
Type	Bug → Task

D4559 starts this.

Trac metadata

Trac field	Value
Differential revisions	- → D4559

changed milestone to %8.8.1

These won't be addressed for GHC 8.6.

changed milestone to %8.10.1

niteria, how is this coming along?

added debug information label

added Pnormal label

removed milestone