Remove -Z miri debugging option

Author: f-bro

src/bootstrap/bin/rustc.rs

@@ -247,9 +247,6 @@ fn main() {
         // When running miri tests, we need to generate MIR for all libraries
         if env::var("TEST_MIRI").ok().map_or(false, |val| val == "true") {
             cmd.arg("-Zalways-encode-mir");
-            if stage != "0" {
-                cmd.arg("-Zmiri");
-            }
             cmd.arg("-Zmir-emit-validate=1");
         }
 

src/bootstrap/test.rs

@@ -875,7 +875,7 @@ impl Step for Compiletest {
         if build.config.rust_debuginfo_tests {
             flags.push("-g".to_string());
         }
-        flags.push("-Zmiri -Zunstable-options".to_string());
+        flags.push("-Zunstable-options".to_string());
         flags.push(build.config.cmd.rustc_args().join(" "));
 
         if let Some(linker) = build.linker(target) {

src/librustc/session/config.rs

@@ -1229,8 +1229,6 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
           "print some statistics about MIR"),
     always_encode_mir: bool = (false, parse_bool, [TRACKED],
           "encode MIR of all functions into the crate metadata"),
-    miri: bool = (false, parse_bool, [TRACKED],
-          "check the miri const evaluator against the old ctfe"),
     osx_rpath_install_name: bool = (false, parse_bool, [TRACKED],
           "pass `-install_name @rpath/...` to the macOS linker"),
     sanitizer: Option<Sanitizer> = (None, parse_sanitizer, [TRACKED],