LocalBearTestHelper: Show better error messages
LocalBearTestHelper: Show better error messages

LocalBearTestHelper was earlier only showing a generic
message if the bear failed to execute. This led to difficulty
in debugging. This commit forces LocalBearTestHelper to show
the error messages from the bear if it wasn't able to execute
successfully.

Fixes https://github.com/coala-analyzer/coala/issues/1405

saurabhiiit/coala,kartikeys98/coala,damngamerz/coala,sudheesh001/coala,rresol/coala,sagark123/coala,shreyans800755/coala,sophiavanvalkenburg/coala,SambitAcharya/coala,tushar-rishav/coala,Uran198/coala,shreyans800755/coala,AbdealiJK/coala,saurabhiiit/coala,djkonro/coala,lonewolf07/coala,yashtrivedi96/coala,scriptnull/coala,refeed/coala,dagdaggo/coala,ManjiriBirajdar/coala,jayvdb/coala,Asnelchristian/coala,RJ722/coala,svsn2117/coala,netman92/coala,jayvdb/coala,SanketDG/coala,svsn2117/coala,dagdaggo/coala,MattAllmendinger/coala,scottbelden/coala,yashLadha/coala,ayushin78/coala,tushar-rishav/coala,swatilodha/coala,NalinG/coala,NiklasMM/coala,NalinG/coala,lonewolf07/coala,arafsheikh/coala,Asalle/coala,coala-analyzer/coala,NalinG/coala,AdeshAtole/coala,aptrishu/coala,JohnS-01/coala,kartikeys98/coala,Shade5/coala,coala/coala,vinc456/coala,arjunsinghy96/coala,Balaji2198/coala,SambitAcharya/coala,coala-analyzer/coala,dagdaggo/coala,stevemontana1980/coala,SambitAcharya/coala,JohnS-01/coala,JohnS-01/coala,Asnelchristian/coala,sudheesh001/coala,CruiseDevice/coala,swatilodha/coala,scriptnull/coala,abhiroyg/coala,mr-karan/coala,scriptnull/coala,MattAllmendinger/coala,d6e/coala,arush0311/coala,MariosPanag/coala,SambitAcharya/coala,djkonro/coala,nemaniarjun/coala,sils1297/coala,karansingh1559/coala,yashtrivedi96/coala,SambitAcharya/coala,yland/coala,ManjiriBirajdar/coala,yashtrivedi96/coala,sophiavanvalkenburg/coala,ManjiriBirajdar/coala,rresol/coala,coala/coala,d6e/coala,Balaji2198/coala,karansingh1559/coala,SanketDG/coala,scottbelden/coala,coala-analyzer/coala,AbdealiJK/coala,NalinG/coala,scriptnull/coala,Nosferatul/coala,scriptnull/coala,Uran198/coala,stevemontana1980/coala,kartikeys98/coala,abhiroyg/coala,karansingh1559/coala,MariosPanag/coala,shreyans800755/coala,tltuan/coala,MattAllmendinger/coala,ayushin78/coala,Uran198/coala,sophiavanvalkenburg/coala,refeed/coala,ayushin78/coala,AdeshAtole/coala,incorrectusername/coala,impmihai/coala,incorrectusername/coala,RJ722/coala,tltuan/coala,Shade5/coala,Nosferatul/coala,arjunsinghy96/coala,meetmangukiya/coala,netman92/coala,SambitAcharya/coala,djkonro/coala,arafsheikh/coala,rresol/coala,yland/coala,meetmangukiya/coala,RJ722/coala,meetmangukiya/coala,AdeshAtole/coala,aptrishu/coala,AbdealiJK/coala,NiklasMM/coala,sagark123/coala,coala/coala,d6e/coala,SambitAcharya/coala,nemaniarjun/coala,yland/coala,NalinG/coala,netman92/coala,arush0311/coala,vinc456/coala,sils1297/coala,mr-karan/coala,damngamerz/coala,refeed/coala,nemaniarjun/coala,jayvdb/coala,svsn2117/coala,damngamerz/coala,NalinG/coala,impmihai/coala,Asalle/coala,NiklasMM/coala,Asnelchristian/coala,arush0311/coala,mr-karan/coala,SanketDG/coala,aptrishu/coala,scriptnull/coala,tushar-rishav/coala,saurabhiiit/coala,impmihai/coala,Asalle/coala,swatilodha/coala,stevemontana1980/coala,rimacone/testing2,sudheesh001/coala,Nosferatul/coala,incorrectusername/coala,rimacone/testing2,CruiseDevice/coala,CruiseDevice/coala,Shade5/coala,rimacone/testing2,vinc456/coala,yashLadha/coala,sagark123/coala,lonewolf07/coala,arafsheikh/coala,yashLadha/coala,Balaji2198/coala,sils1297/coala,MariosPanag/coala,abhiroyg/coala,arjunsinghy96/coala,scottbelden/coala,scriptnull/coala,tltuan/coala,NalinG/coala