Remove the std workspace patch for compiler-builtins

All dependencies of `std` have dropped the crates.io dependency on
`compiler-builtins`, so this patch is no longer needed.

Closes: RUST-142265

library/Cargo.toml

@@ -59,4 +59,3 @@ rustflags = ["-Cpanic=abort"]
 rustc-std-workspace-core = { path = 'rustc-std-workspace-core' }
 rustc-std-workspace-alloc = { path = 'rustc-std-workspace-alloc' }
 rustc-std-workspace-std = { path = 'rustc-std-workspace-std' }
-compiler_builtins = { path = "compiler-builtins/compiler-builtins" }