CI: use a wrapper script to generate coverage report

5 jobs for ci_coverage in 52 minutes and 59 seconds (queued for 9 seconds)
Status Job ID Name Coverage
  Prepare
passed #7557
ubuntu-xdk-prepare

00:03:04

 
  Build
passed #7558
ubuntu-xdk-qa-code-coverage

00:47:27

passed #7559
ubuntu-xdk-qa-static-analysis

00:32:03

 
  Report
passed #7560
ubuntu-xdk-report

00:02:27

 
  External
passed cdash:ubuntu-18.04-llvm-qa