For the time being the following workaround can be used:
CSS:
	<style type="text/css">
		@media screen and (-webkit-min-device-pixel-ratio: 0) {
			.RadForm.rfdRadio input[type="radio"] + label,
			.RadForm.rfdCheckbox input[type="checkbox"] + label {
				display: inline !important;
				vertical-align: bottom !important;
			}
		}


		.RadForm.rfdCheckbox .rfdCheckboxChecked + label, 
		.RadForm.rfdCheckbox .rfdCheckboxUnchecked + label,
		.RadForm.rfdRadio .rfdRadioChecked + label, 
		.RadForm.rfdRadio .rfdRadioUnchecked + label {
			display: inline !important;
		}
	</style>
ASPX:
	<form id="form1" runat="server">
		<telerik:RadScriptManager ID="RadScriptManager1" runat="server"></telerik:RadScriptManager>
		<telerik:RadFormDecorator ID="RadFormDecorator1" runat="server" DecoratedControls="All" RenderMode="Lightweight" />
		<input id="myRadio" type="radio" name="name" value="val1" />
		<label for="myRadio">some long text some long text some long text some long text some long text some long text</label>
		<br />
		<input id="myCheckBox" type="checkbox" name="name" value="val2" />
		<label for="myCheckBox">some long text some long text some long text some long text some long text some long text</label>
	</form>