cmd/commands: fix to read debug info file from correct directory in trace command

[nozzy123nozzy]

I use dlv 1.20.2 (the latest). I experienced the problem that dlv trace -e always fails to read separated debug info like the below,

$ ~/go/bin/dlv trace --log -e /usr/bin/hugo 'commands\.new.*'
2023-06-05T01:50:12+09:00 info layer=debugger launching process with args: [/usr/bin/hugo]                                                                          
2023-06-05T01:50:12+09:00 warning layer=debugger gnu_debuglink link "7c03fe5487be2cbd7f7097fae18a1337dc56bf.debug" not found in any debug info directory            
could not launch process: could not open debug info - debuggee must not be built with 'go run' or -ldflags='-s -w', which strip debug info

The root cause is that the traceCmd function in cmd/dlv/cmds/commands.go doesn't reference conf.DebugInfoDirectories, therefore, openSeparateDebugInfo function in pkg/proc/bininfo.go tries to find the debug info in the wrong directory.

I suggest this PR to fix this problem.

[aarzilli]

LGTM

[derekparker]

LGTM