Use public-dependencies in all sysroot crates

In [1], most dependencies of `std` and other sysroot crates were marked
private, but this did not happen for `alloc` and `test`. Update these
here, marking public standard library crates as the only non-private
dependencies.

[1]: rust-lang/rust#111076

Author: tgross35

patches/0029-stdlib-Disable-f16-and-f128-in-compiler-builtins.patch

@@ -15,7 +15,7 @@ index 7165c3e48af..968552ad435 100644
  edition = "2021"
 
  [dependencies]
- core = { path = "../core" }
+ core = { path = "../core", public = true }
 -compiler_builtins = { version = "=0.1.146", features = ['rustc-dep-of-std'] }
 +compiler_builtins = { version = "=0.1.146", features = ['rustc-dep-of-std', 'no-f16-f128'] }