Remove handcrafted librustc_demangle_static am: 59b25ff22a

Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/rustc-demangle-capi/+/2795153

Change-Id: I47f0d9fdae59edf0af7490b6accd2cc25e62f832
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>