PR #11425: [XLA:GPU] Add sycl platform
PR #11425: [XLA:GPU] Add sycl platform

Imported from GitHub PR https://github.com/openxla/xla/pull/11425

It is a sub PR of https://github.com/openxla/xla/pull/9042 to add sycl platform
Copybara import of the project:

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7d0c37057c673f784089ce961d24276a496d43bd by Sheng, Yang <yang.sheng@intel.com>:

Add sycl platform

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8d1196831a20f69ba8880d8549007358928f6be1 by Sheng, Yang <yang.sheng@intel.com>:

Add comments back

Merging this change closes #11425

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/11425 from Intel-tensorflow:yang/sycl-platform 8d1196831a20f69ba8880d8549007358928f6be1
