add a4 tests

Tests/A4/Je_7_Reachability_WhileFalse_Empty.java

Tests/A4/Je_7_Reachability_WhileFalse_IfThenElse.java

Tests/A4/Je_7_Reachability_WhileTrue.java

Tests/A4/Je_7_Reachability_WhileTrue_ConstantFolding.java

Tests/A4/Je_7_Return_IfElseIf.java

Tests/A4/Je_7_Return_IfIfNoElseElse.java

Tests/A4/Je_7_Return_IfIfNot.java

Tests/A4/Je_7_Return_MissingInElse.java

Tests/A4/Je_8_DefiniteAssignment_ArrayAssign.java

Tests/A4/Je_8_DefiniteAssignment_ArrayIndexAssign.java

Tests/A4/Je_8_DefiniteAssignment_ComplexInitializer.java

Tests/A4/Je_8_DefiniteAssignment_FalseAndAssignment.java

Tests/A4/Je_8_DefiniteAssignment_FieldWithSameName.java

Tests/A4/Je_8_DefiniteAssignment_IfIfNot.java

Tests/A4/Je_8_DefiniteAssignment_InitToItself.java

Tests/A4/Je_8_DefiniteAssignment_SomethingAndAssignment.java

Tests/A4/Je_8_DefiniteAssignment_SomethingOrAssignment.java

.../A4/Je_8_DefiniteAssignment_UninitializedExpInLvalue.java

...s/A4/Je_8_DefiniteAssignment_UninitializedInNewArray.java

Tests/A4/Je_8_DefiniteAssignment_WhileFalse.java