Disable asm lint example tests since they only work on x86_64

Author: Amanieu

Diff for: compiler/rustc_lint_defs/src/builtin.rs

@@ -2419,7 +2419,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust
+    /// ```rust,ignore (fails on non-x86_64)
     /// #[cfg(target_arch="x86_64")]
     /// use std::arch::asm;
     ///
@@ -2455,7 +2455,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust
+    /// ```rust,ignore (fails on non-x86_64)
     /// #[cfg(target_arch="x86_64")]
     /// use std::arch::asm;
     ///