NPE when allocate has both AR and AP invoice

1. create and complete AR Invoice

2. create and complete AP Invoice

3. Create Allocation and add 2 invoice to lines

4. complete Allocation then posting get error NPE (Posting Error (java.lang.NullPointerException))

reference example:

or add bellow unit test to AllocationTest and run it

Reason:

1. Doc_AllocationHdr.createFacts

   1. bpAcct is ACCTTYPE_C_Receivable in case AR invoice

   2. bpAcct is ACCTTYPE_V_Liability in case AP invoice

2. Doc_AllocationHdr.createInvoiceRoundingCorrection

   1. it query posting of invoice use bpAcct, but value of bpAcct depend on kind of invoice on last allocation line

   2. so in case last allocation line is AR Invoice then Doc_AllocationHdr.createInvoiceRoundingCorrection for AP invoice get NPE and vice versa