test: fix cleanup order in ULTs

- program using device must be released before device is destroyed.
Reset program unique_ptr in fixtures before device fixture tearDown()
- reorder fixtures members to ensure correct order of destructors

Signed-off-by: Mateusz Hoppe <mateusz.hoppe@intel.com>

opencl/test/unit_test/helpers/base_object_tests.cpp

@@ -88,6 +88,9 @@ template <>
 class MockObject<Program> : public MockObjectBase<Program> {
   public:
     MockObject() : MockObjectBase<Program>(nullptr, false, toClDeviceVector(*(new MockClDevice(new MockDevice())))), device(this->clDevices[0]) {}
+    ~MockObject() override {
+        Program::clDevices.clear();
+    }
 
   private:
     std::unique_ptr<ClDevice> device;