testsuite: Make test for issue1091 re-runnable ...

After the initial run, one couldn't run this test again as the expected message
'building configuration' would not be printed anymore.

replace all usages of `exit` ...

- those skipped the ERR trap
- add die function to exit with line number and message

unify flags and error handling ...

- also add trap ERR handler to report exact error location

Add test for #1091.