Remove dead code and docs

src/bin/cargo-miri.rs

@@ -25,13 +25,6 @@ Common options:
 Other [options] are the same as `cargo rustc`.  Everything after the first "--" is
 passed verbatim to Miri, which will pass everything after the second "--" verbatim
 to the interpreted program.
-
-The config flag `miri` is automatically defined for convenience. You can use
-it to configure the resource limits
-
-    #![cfg_attr(miri, memory_size = 42)]
-
-available resource limits are `memory_size`, `step_limit`, `stack_limit`
 "#;
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]

tests/compile-fail/stack_limit.rs

@@ -1,20 +0,0 @@
-#![feature(custom_attribute)]
-#![miri(stack_limit=16)]
-
-//error-pattern: reached the configured maximum number of stack frames
-
-fn bar() {
-    foo();
-}
-
-fn foo() {
-    cake();
-}
-
-fn cake() {
-    bar();
-}
-
-fn main() {
-    bar();
-}