Test Expr can be reported differently with log benchmarking

[emccorkle]

The test expr is reported differently for ut assert value when log benchmarking is enabled. This is related to UtBufferingReporter used in the implementation of log benchmarking.

ut test("A", "a", Expr( ut assert value(10, 20) ), ut log bench(-1));
FAILURE  Test #1: Expr(10) equal to 20 (A ⮚ a ⮚ 1) 
                  ^ === HERE ===
            
ut test("A", "b", Expr( ut assert value(10, 20) ), ut log bench(0));
FAILURE  Test #2: 10 equal to 20 (A ⮚ b ⮚ 1) 
                  ^ === VERSUS HERE ===