The breakage was introduced by the following commit :
ae07801dd8
After the commit, HIPCC errors out on some tests with the following error
```
Building HIPCC object unsupported/test/CMakeFiles/cxx11_tensor_device_1.dir/cxx11_tensor_device_1_generated_cxx11_tensor_device.cu.o
In file included from /home/rocm-user/eigen/unsupported/test/cxx11_tensor_device.cu:17:
In file included from /home/rocm-user/eigen/unsupported/Eigen/CXX11/Tensor💯
/home/rocm-user/eigen/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h:129:12: error: no matching constructor for initialization of 'Eigen::internal::TensorBlockResourceRequirements'
return {merge(lhs.shape_type, rhs.shape_type), // shape_type
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/rocm-user/eigen/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h:75:8: note: candidate constructor (the implicit copy constructor) not viable: requires 1 argument, but 3 were provided
struct TensorBlockResourceRequirements {
^
/home/rocm-user/eigen/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h:75:8: note: candidate constructor (the implicit move constructor) not viable: requires 1 argument, but 3 were provided
/home/rocm-user/eigen/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h:75:8: note: candidate constructor (the implicit copy constructor) not viable: requires 5 arguments, but 3 were provided
/home/rocm-user/eigen/unsupported/Eigen/CXX11/src/Tensor/TensorBlock.h:75:8: note: candidate constructor (the implicit default constructor) not viable: requires 0 arguments, but 3 were provided
...
...
```
The fix is to explicitly decalre the (implicitly called) constructor as a device func
* Abstracting the pointer type so that both SYCL memory and pointer can be captured.
* Converting SYCL virtual pointer to SYCL device memory in Eigen evaluator class.
* Binding SYCL placeholder accessor to command group handler by using bind method in Eigen evaluator node.
* Adding SYCL macro for controlling loop unrolling.
* Modifying the TensorDeviceSycl.h and SYCL executor method to adopt the above changes.
