Added missing UninterpretedZ3Solver, source of many failed tests.

src/main/scala/leon/solvers/SolverFactory.scala

@@ -156,6 +156,8 @@ object SolverFactory {
       SolverFactory(() => new SMTLIBCVC4Solver(ctx, program) with TimeoutSolver)
     } else if(names contains "smt-z3") {
       SolverFactory(() => new SMTLIBZ3Solver(ctx, program) with TimeoutSolver)
+    } else if ((names contains "fairz3") && hasNativeZ3) {
+      SolverFactory(() => new UninterpretedZ3Solver(ctx, program) with TimeoutSolver)
     } else {
       ctx.reporter.fatalError("No SMT solver available: native Z3 api could not load and 'cvc4' or 'z3' binaries were not found in PATH.")
     }

src/test/scala/leon/test/LeonRegressionSuite.scala

@@ -33,7 +33,7 @@ trait LeonRegressionSuite extends FunSuite with Timeouts {
         body
       } catch {
         case fe: LeonFatalError =>
-          throw new TestFailedException("Uncaught LeonFatalError", fe, 5)
+          throw new TestFailedException("Uncaught LeonFatalError" + fe.msg.map(": " + _).getOrElse(""), fe, 5)
       }
     }
   }