Bug 195607 NPE is thrown when calling DimensionHandle:: getAbsoluteValue()
If a DimensionHandle did not set DimensionValue, NPE will thrown when calling DimensionHandle:: getAbsoluteValue().
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/DimensionHandle.java
{
	/**
	 * Constructs a dimension handle for a member of a structure. This member
	 * must be a dimension type.
	 *