Catch unexpected WebGPU errors. (#4475)

* Catch unexpected WebGPU errors.

A recent change accidentally stopped catching
unexpected WebGPU errors. 

Co-authored-by: Kai Ninomiya <[email protected]>

Author: greggman

src/webgpu/util/device_pool.ts

@@ -129,6 +129,8 @@ export class DevicePool {
           await attemptGarbageCollection();
         }
       }
+
+      throw ex;
     } finally {
       const deviceDueForReplacement =
         holder.testCaseUseCounter >= globalTestConfig.casesBetweenReplacingDevice;