The code to write exception handlers in DirectCodeBuilder has an incorrect `handlersSize++`, which means a mix and match of dead and valid exception handlers can lead to malformed class files. Verified with a simple test that throws ConstantPoolException:

    @Test
    void testFilterMixedExceptionCatch() {
        var cc = ClassFile.of(ClassFile.DeadLabelsOption.DROP_DEAD_LABELS);
        var code = cc.parse(cc.build(CD_Void, clb ->
                clb.withMethodBody("m", MTD_void, 0, cob -> {
                    cob.return_();
                    var l = cob.newBoundLabel();
                    cob.pop().return_();
                    cob.exceptionCatch(cob.startLabel(), l, l, Optional.empty());
                    cob.exceptionCatch(cob.newLabel(), l, l, CD_Exception);
                }))).methods().get(0).code().get();
        assertEquals(1, code.exceptionHandlers().size(), () -> code.exceptionHandlers().toString());
        assertEquals(Optional.empty(), code.exceptionHandlers().getFirst().catchType());
    }