stream: add track_caller to public APIs (#4786)

Functions that may panic can be annotated with `#[track_caller]` so that
in the event of a panic, the function where the user called the
panicking function is shown instead of the file and line within Tokio
source.

This change adds `#[track_caller]` to all the non-unstable public APIs
in tokio-stream (only `chunks_timeout` in `StreamExt`) where the
documentation describes how this function may panic due to incorrect
input.

A test has been included to cover the panic.

Refs: #4413

tokio-stream/Cargo.toml

@@ -34,6 +34,7 @@ tokio-util = { version = "0.7.0", path = "../tokio-util", optional = true }
 [dev-dependencies]
 tokio = { version = "1.2.0", path = "../tokio", features = ["full", "test-util"] }
 async-stream = "0.3"
+parking_lot = "0.12.0"
 tokio-test = { path = "../tokio-test" }
 futures = { version = "0.3", default-features = false }