TMP: Remove bitcoind-tests

`bitcoind-tests` has a dependency on `bitcoin` so it makes depending on
a local patched version more difficult, just temporarily delete it.

Author: tcharding

Cargo.toml

@@ -66,5 +66,5 @@ name = "big"
 required-features = ["std", "base64", "compiler"]
 
 [workspace]
-members = ["bitcoind-tests", "fuzz"]
+members = ["fuzz"]
 exclude = ["embedded"]