Fix tool crashing when lines end with cr(not crlf)

[SenRamakri]

Description

Fix tool crashing when lines end with just cr (not crlf)

Pull request type

[x] Fix
[ ] Refactor
[ ] New target
[ ] Feature
[ ] Breaking change

[cmonr]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2465
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7356/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2094
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7356/

[mbed-ci]

Test : SUCCESS

Build number : 2241
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7356/2241

[bmcdonnell-ionx]

I see that your fix should handle CR, LF, and CRLF linebreaks, as described here. Nice. 😃