integration-test: update rust toolchain

The data-layout string is necessary because of
https://github.com/rust-lang/rust/commit/8b199222cc92667cd0e57595ad435cd0a7526af8

integration-test/bins/rust-toolchain.toml

@@ -1,5 +1,5 @@
 [toolchain]
-channel = "nightly-2023-06-22"
+channel = "nightly-2024-03-31" # rustc 1.79-nightly
 profile = "default"
 components = [
     "rust-src",

integration-test/bins/x86-unknown-none.json

@@ -1,6 +1,6 @@
 {
     "llvm-target": "i686-unknown-none",
-    "data-layout": "e-m:e-i32:32-f80:128-n8:16:32-S128-p:32:32",
+    "data-layout": "e-m:e-p:32:32-p270:32:32-p271:32:32-p272:64:64-i128:128-f64:32:64-f80:32-n8:16:32-S128",
     "arch": "x86",
     "target-endian": "little",
     "target-pointer-width": "32",