If debug info generation is enabled, set debug location to the
coroutine call instruction to make sure there are no issues with invalid
debug information in LTO.
This happens because in LTO, if a call to a function doesn't contain a
debug location, we see the warning:
inlinable function call in a function with debug info must have a
!dbg location
ld: warning: Invalid debug info found, debug info will be stripped
Which then strips the debug info from the entire .o file linked into the
dylib.
