Use only first device for each device type and backend (#118)

Author: PokhodenkoSA

backends/source/dppl_sycl_queue_manager.cpp

@@ -75,8 +75,15 @@ class QMgrHelper
                 vector_class<device> SelectedDevices;
                 for(auto &d : Devices) {
                     auto devty = d.get_info<info::device::device_type>();
-                    if(devty == DTy && be == BE)
+                    if(devty == DTy && be == BE) {
                         SelectedDevices.push_back(d);
+
+                        // Workaround for situations when in some environments
+                        // get_devices() returns each device TWICE. Then it fails in call
+                        // for context constructor with all doubled devices.
+                        // So use only one first device.
+                        break;
+                    }
                 }
                 if (SelectedDevices.size() > 0) {
                     auto Ctx = context(SelectedDevices);