RFR: 7903875: Extend RecordContainerTest to also verify plain coverage report

[Alexandre Iline]

…verage report

-------------

Commit messages:
 - CODETOOLS-7903875: Extend RecordContainerTest to also verify plain coverage report

Changes: https://git.openjdk.org/jcov/pull/53/files
  Webrev: https://webrevs.openjdk.org/?repo=jcov&pr=53&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903875
  Stats: 22 lines in 1 file changed: 20 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jcov/pull/53.diff
  Fetch: git fetch https://git.openjdk.org/jcov.git pull/53/head:pull/53

PR: https://git.openjdk.org/jcov/pull/53