Remove TestRandom (#9006)

We  have a legacy `TestRandom` trait which generates random types for testing and fuzzing.
This function overlaps with `arbitrary` which is used very commonly in the ecosystem.


  Remove `TestRandom` and generate random type instances using `Arbitrary`.


Co-Authored-By: Mac L <mjladson@pm.me>

Co-Authored-By: Michael Sproul <michael@sigmaprime.io>

common/test_random_derive/Cargo.toml

@@ -1,13 +0,0 @@
-[package]
-name = "test_random_derive"
-version = "0.2.0"
-authors = ["thojest <thojest@gmail.com>"]
-edition = { workspace = true }
-description = "Procedural derive macros for implementation of TestRandom trait"
-
-[lib]
-proc-macro = true
-
-[dependencies]
-quote = { workspace = true }
-syn = { workspace = true }