Rename Key.name to Key.debugName

This CL simply renames (Element|Scene|Value)Key.name to .debugName to
make it more obvious that the name is only used for debugging/printing
and does not change anything in the correctness of the code.

Bug: 291053742
Test: atest PlatformComposeCoreTests
Change-Id: I6b4d256db3e0ad5dd995fcd2b95b73efb4919350
3 files changed