(iOS) Fix empty failure tag on JUnit XML report when unknown class

[msd117c]

Proposal to fix the issue reported here.

When the xcode execution log prints a test failure with an unknown class, the parser does not detect the error trace with the current regex expression, expecting a proper class path (/path/to/class):

...
<DebugLogPrinter> <unknown>:0: error: -[TestTarget.Tests testAccessibility] : Element has no description
<DebugLogPrinter>     t =     4.79s Find the Any (Descendant with identity binding to AX element pid: 62723, elementOrHash.elementID: 105553170498336.190)
<DebugLogPrinter>     t =     4.80s Checking existence of `"empty state view" StaticText`
<DebugLogPrinter>     t =     4.81s Find the "empty state view" StaticText
...

which results into the following failure tag:

    ...
    <testcase name="testAccessibility" time="13.387" classname="TestTarget.Tests">
      <failure></failure>
    </testcase>
    ...

For now I do not understand why the log says "unknown" class. However, this change would provide some information on the JUnit XML report about the stacktrace, as a first step to tackle the issue.

Note 1: When multiline stacktrace the parser only captures the first line.
Note 2: as an additional change the related test could be parameterized to simplify the addition of new tests / maintenance of the test.

[Malinskiy]

<unknown>:0: error indicates a failure in some compiler-generated code that doesn't have a source, hence it has nothing to point to. Approved.

[Malinskiy]

Appreaciate the time to redo this properly