Auto merge of rust-lang#133369 - Zalathar:profiler-builtins-no-core, r=jieyouxu

Allow injecting a profiler runtime into `#![no_core]` crates

An alternative to rust-lang#133300, allowing `-Cinstrument-coverage` to be used with `-Zbuild-std`.

The incompatibility between `profiler_builtins` and `#![no_core]` crates appears to have been caused by profiler_builtins depending on core, and therefore conflicting with core (or minicore).

But that's a false dependency, because the profiler doesn't contain any actual Rust code. So we can just mark the profiler itself as `#![no_core]`, and remove the incompatibility error.

---

For context, the error was originally added by rust-lang#79958.

Author: bors

Cargo.lock

@@ -9,8 +9,6 @@ bench = false
 doc = false
 
 [dependencies]
-core = { path = "../core" }
-compiler_builtins = { version = "0.1.0", features = ['rustc-dep-of-std'] }
 
 [build-dependencies]
 cc = "1.2"

profiler_builtins/Cargo.toml

@@ -1,11 +1,15 @@
-#![no_std]
+// tidy-alphabetical-start
+#![allow(internal_features)]
+#![feature(no_core)]
 #![feature(profiler_runtime)]
+#![feature(staged_api)]
+// tidy-alphabetical-end
+
+// Other attributes:
+#![no_core]
 #![profiler_runtime]
 #![unstable(
     feature = "profiler_runtime_lib",
     reason = "internal implementation detail of rustc right now",
     issue = "none"
 )]
-#![allow(unused_features)]
-#![allow(internal_features)]
-#![feature(staged_api)]