Fix CompositePK_Test tests.
Fix CompositePK_Test tests.

The CompositePK_Test.CP2_UpdateTableWithCompositePK() and
CompositePK_Test.CP3_DeleteTableWithCompositePK() tests were failing under
L2SQL for several reasons:

 1. They used OrderID=3 and ProductID=2, and the MS SQL Northwind DB doesn't
    have any Orders with OrderID=3.
 2. Once that was fixed, there was a constraint violation as the Northwind DB
    requires that [Order Details].Quantity be >= 0.
 3. Of the 2120 [Order Details] entries, there were several with a UnitPrice
    of both 20 and 40, thus breaking CP2's .Single() use.

We fix these by dynamically retrieving the OrderID and ProductID values (1),
providing a "sentinel" TestQuantity value (fixes (2), and allows sane
cleanup), and using "very probably unique" values for the UnitPrice (3).

These tests now pass under L2SQL and DbLinq.SqlServer.


git-svn-id: 1800f71f313d917366f95485fa960eed04b40598@1113 33146b6e-df29-0410-a1ca-39be37fb9416

Sectoid/dblinq,Sectoid/dblinq,sharique/dbinq,sharique/dbinq