compiler/calls intermittently fail when running with Graal as JIT.
All failures pretty much the same and look like "Unexpected caller compilation level: expected 4 to equal 0".

I did modify CallsBase:compileMethod by adding check wb.isMethodCompiled(method)

    protected final void compileMethod(Method method, int compLevel) {
        wb.deoptimizeMethod(method);
        Asserts.assertTrue(wb.isMethodCompilable(method, compLevel));
        wb.enqueueMethodForCompilation(method, compLevel);

        boolean waited = false;
        long startTime = System.currentTimeMillis();
        while (! wb.isMethodCompiled(method)) {
            try { Thread.sleep(10); } catch (Exception e) {}
            waited = true;
        }
        if (waited)
            System.out.println("Waited for method being compiled " + (System.currentTimeMillis() - startTime) + " ms");
    }

and I see that from run to run we can wait up to 100 ms for method being compiled.

I also verified that wb.enqueueMethodForCompilation returns true.
So it looks like the Graal compilation is not blocking although we run with -Xbatch.