integration-test: Don't set rust-lld as a linker

The recommendation (coming from rust-lang/rust#130062) is using C
compiler driver as a linker, which is able to find system-wide
libraries. Using linker binaries directly in `-C linker` (e.g.
`-C linker=rust-lld`) often results in errors like:

```
cargo:warning=error: linking with `rust-lld` failed: exit status: 1ger, ppv-lite86, libc...
cargo:warning=  |
cargo:warning=  = note: LC_ALL="C" PATH="/home/vadorovsky/.rustup/toolchains/stable-x86_64-un
cargo:warning=  = note: rust-lld: error: unable to find library -lgcc_s
cargo:warning=          rust-lld: error: unable to find library -lc
cargo:warning=
cargo:warning=
cargo:warning=
cargo:warning=error: aborting due to 1 previous error
```

Fixes aya-rs#907

xtask/src/run.rs

@@ -55,12 +55,10 @@ pub fn build<F>(target: Option<&str>, f: F) -> Result<Vec<(String, PathBuf)>>
 where
     F: FnOnce(&mut Command) -> &mut Command,
 {
-    // Always use rust-lld and -Zbuild-std in case we're cross-compiling.
     let mut cmd = Command::new("cargo");
     cmd.args(["build", "--message-format=json"]);
     if let Some(target) = target {
-        let config = format!("target.{target}.linker = \"rust-lld\"");
-        cmd.args(["--target", target, "--config", &config]);
+        cmd.args(["--target", target]);
     }
     f(&mut cmd);