Fix UseScanManager.isValidArchive() and UseReportConverter

[HannesWell]

In UseScanManager.isValidArchive() the jar/zip-file was closed too early making it impossible to read from it.

And in UseReportConverter.getXML() the default look up looked not at the wrong file when computing the filtered-counts.

Since especially the former seems to be broken for some time I wonder if API use-scans are a used feature?
Does anybody know if the is used for the Eclipse SDK or SimRel? With that I could verify if this really is fixed (at the moment this is just an anticipated fix from looking at the code). Maybe @merks or @iloveeclipse?

[merks]

I imagine/expect they are only used if it can be used via Tycho.

[github-actions]

Test Results

   291 files  ±0     291 suites  ±0   53m 5s ⏱️ + 1m 17s
 3 526 tests ±0   3 468 ✅ ±0   58 💤 ±0  0 ❌ ±0 
10 875 runs  ±0  10 698 ✅ ±0  177 💤 ±0  0 ❌ ±0 

Results for commit fb74b56. ± Comparison against base commit 0d546e9.

[laeubi]

Sometimes these things are made available as an Ant Task and then called by scripts. Beside that Tychon "only" calls the BaseApiAnalyzer so whatever is analyzed there will be used.

[HannesWell]

The code (probably) broken is only called by the preference-page. My remark was meant if API use-scans are used in general and if anybody knows a place where some are produced so that I could use them as sample or if I had to create them by myself.

[HannesWell]

Let's submit this, although I cannot test this at the moment, it should not make it worse and I expect to improve the situation.