Remove compiler-builtins from rustc-dep-of-std dependencies

Since [1], this will come automatically from `rustc-std-workspace-core`
and the crates.io dependency should no longer be specified.

[1]: rust-lang/rust#141993

Author: tgross35

Cargo.toml

@@ -27,7 +27,6 @@ rust-version = "1.68"
 [dependencies]
 r-efi = "5.2.0"
 # Required setup to build as part of rustc.
-compiler_builtins = { version = '0.1.79', optional = true }
 core = { version = '1.0.0', optional = true, package = 'rustc-std-workspace-core' }
 
 [features]
@@ -41,7 +40,7 @@ native = []
 # This feature-gate is a requirement to integrate crates into the dependency
 # tree of the standard library. Use outside of the standard library is not
 # supported.
-rustc-dep-of-std = ['compiler_builtins/rustc-dep-of-std', 'core']
+rustc-dep-of-std = ['core']
 
 [[example]]
 name = "hello-world"