Remove handcrafted librustc_demangle_static am: 59b25ff22a am: eecfc6df8c

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

Change-Id: Iabaa9b8ef4ded3e41e0e1434691fe43c48b74c9d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>