Skip building binaries in when there are no tests (#8820)

## Rationale for this change

We have many binaries in the main workspace, many of them don't contain
any tests (in the final `main.rs` or equivalent file).

## What changes are included in this PR?

Sets `test = false` for most binaries in the workspace, which means that
running `cargo test` or `cargo nextest` won't build the final binary.

I've also restructured `random-access` a bit (with claude's help) so it
actually has a dedicated `lib.rs`.

## What APIs are changed? Are there any user-facing changes?

None

Signed-off-by: Adam Gutglick <adam@spiraldb.com>

Author: AdamGS

benchmarks/compress-bench/Cargo.toml

@@ -37,5 +37,12 @@ vortex-bench = { workspace = true }
 lance = ["dep:lance-bench"]
 unstable_encodings = ["vortex/unstable_encodings"]
 
+[[bin]]
+name = "compress-bench"
+test = false
+
+[lib]
+test = false
+
 [lints]
 workspace = true

benchmarks/datafusion-bench/Cargo.toml

@@ -17,6 +17,13 @@ publish = false
 [package.metadata.cargo-shear]
 ignored = ["vortex-cuda"]
 
+[[bin]]
+name = "datafusion-bench"
+test = false
+
+[lib]
+test = false
+
 [dependencies]
 anyhow = { workspace = true }
 clap = { workspace = true, features = ["derive"] }

benchmarks/duckdb-bench/Cargo.toml

@@ -17,6 +17,13 @@ publish = false
 [package.metadata.cargo-shear]
 ignored = ["vortex-cuda"]
 
+[[bin]]
+name = "duckdb-bench"
+test = false
+
+[lib]
+test = false
+
 [dependencies]
 anyhow = { workspace = true }
 clap = { workspace = true, features = ["derive"] }

benchmarks/lance-bench/Cargo.toml

@@ -32,5 +32,12 @@ vortex-bench = { workspace = true }
 [features]
 unstable_encodings = ["vortex-bench/unstable_encodings"]
 
+[lib]
+test = false
+
+[[bin]]
+name = "lance-bench"
+test = false
+
 [lints]
 workspace = true

benchmarks/random-access-bench/Cargo.toml

@@ -29,5 +29,9 @@ vortex-bench = { workspace = true }
 lance = ["dep:lance-bench"]
 unstable_encodings = ["vortex-bench/unstable_encodings"]
 
+[[bin]]
+name = "random-access-bench"
+test = false
+
 [lints]
 workspace = true