Add copyBufferToBuffer tests to CTS test list

(This doesn't actually enable the tests for the new overloads, because
of a different error reporting issue that affects many CTS tests
including these. But if you run the tests for the new overloads
manually, before and after the fix, you can see that the behavior has
changed.)

Author: andyleiserson

cts_runner/test.lst

@@ -1,5 +1,10 @@
 unittests:*
 webgpu:api,operation,command_buffer,basic:*
+webgpu:api,operation,command_buffer,copyBufferToBuffer:single:newSig=false;*
+// https://github.com/gfx-rs/wgpu/issues/7391
+//FAIL: webgpu:api,operation,command_buffer,copyBufferToBuffer:single:newSig=true;*
+webgpu:api,operation,command_buffer,copyBufferToBuffer:state_transitions:*
+webgpu:api,operation,command_buffer,copyBufferToBuffer:copy_order:*
 webgpu:api,operation,compute,basic:memcpy:*
 //FAIL: webgpu:api,operation,compute,basic:large_dispatch:*
 webgpu:api,operation,device,lost:*