Fix VanillaExceptionTracker to output only unexpected exceptions in AssertionError message

[maxim-ponomarev]

At the moment, if there are any unexpected exceptions, AssertionError message contains ALL recorded exceptions, it doesn't honor ignorePredicate.

Chronicle-Test-Framework/src/main/java/net/openhft/chronicle/testframework/internal/VanillaExceptionTracker.java

Line 126 in c05e329

final String msg = exceptions.size() + " exceptions were detected: " + exceptions.keySet().stream().map(messageExtractor::apply).collect(Collectors.joining(", "));