Revert "Revert json ops (denoland#2814)"

This reverts commit 2235dd7.

cli/deno_error.rs

@@ -205,6 +205,18 @@ impl GetErrorKind for ReadlineError {
   }
 }
 
+impl GetErrorKind for serde_json::error::Error {
+  fn kind(&self) -> ErrorKind {
+    use serde_json::error::*;
+    match self.classify() {
+      Category::Io => ErrorKind::InvalidInput,
+      Category::Syntax => ErrorKind::InvalidInput,
+      Category::Data => ErrorKind::InvalidData,
+      Category::Eof => ErrorKind::UnexpectedEof,
+    }
+  }
+}
+
 #[cfg(unix)]
 mod unix {
   use super::{ErrorKind, GetErrorKind};
@@ -251,6 +263,11 @@ impl GetErrorKind for dyn AnyError {
       .or_else(|| self.downcast_ref::<uri::InvalidUri>().map(Get::kind))
       .or_else(|| self.downcast_ref::<url::ParseError>().map(Get::kind))
       .or_else(|| self.downcast_ref::<ReadlineError>().map(Get::kind))
+      .or_else(|| {
+        self
+          .downcast_ref::<serde_json::error::Error>()
+          .map(Get::kind)
+      })
       .or_else(|| unix_error_kind(self))
       .unwrap_or_else(|| {
         panic!("Can't get ErrorKind for {:?}", self);

cli/main.rs

@@ -32,7 +32,6 @@ mod http_body;
 mod http_util;
 mod import_map;
 pub mod msg;
-pub mod msg_util;
 pub mod ops;
 pub mod permissions;
 mod progress;