Test scopes with unavailable values

Running test: testTemporalDeadZone
variable y correctly reported as <value_unavailable>

Running test: testOptimizedOut
variable y correctly reported as <value_unavailable>

Running test: testUnusedValueInTdz
variable y correctly reported as <value_unavailable>

Running test: testVarStaysUndefined
variable y correctly reported as <undefined>
