Fixed DSYM for mac

[swamishiju]

I was facing some problems with lldb locally for lpython which i didnt with lfortran so i wrote a small fix for it

before

lpython % lldb src/bin/lpython
(lldb) target create "src/bin/lpython"
warning: (arm64) /Users/swaminathshiju/lpython/src/bin/lpython empty dSYM file detected, dSYM was created with an executable with no debug info.
Current executable set to '/Users/swaminathshiju/lpython/src/bin/lpython' (arm64).
(lldb)

after

lpython % lldb src/bin/lpython
(lldb) target create "src/bin/lpython"
Current executable set to '/Users/swaminathshiju/lpython/src/bin/lpython' (arm64).
(lldb)

[ubaidsk]

It looks like we added similar changes for lfortran here. I think this should be good.