ExceptionsHelper might enter infinite loops or fail with a stack overflow

[jpountz]

Cycles in exceptions' causes or suppressions can trigger bugs, try to run eg. the following tests:

    public void testSuppressedCycle() {
        RuntimeException e1 = new RuntimeException();
        RuntimeException e2 = new RuntimeException();
        e1.addSuppressed(e2);
        e2.addSuppressed(e1);
        ExceptionsHelper.unwrapCorruption(e1);
    }

    public void testCauseCycle() {
        RuntimeException e1 = new RuntimeException();
        RuntimeException e2 = new RuntimeException(e1);
        e1.initCause(e2);
        ExceptionsHelper.unwrapCorruption(e1);
    }

The first one fails with a StackOverflowError and the second one enters an infinite loop. It occurred to me while giving another look at #41889 but this is a pre-existing issue.

cc @original-brownbear

[elasticmachine]

Pinging @elastic/es-distributed