Rollup merge of #66478 - petrochenkov:rmplugin, r=davidtwco

rustc_plugin: Remove the compatibility shim

The compatibility crate was introduced in https://github.com/rust-lang/rust/pull/62727 to migrate Cargo and some other tools, but now it's no longer necessary.

diff --combined Cargo.lock
index 7eb5d4b464c06e18ab4dd5ae126c21b9a58a2b8c,1923032a4dd0cdac7fae3764589979d68f425719..84e0d44d938d81863b26ff16c1c8edbbc9f91b2f
--- 1/Cargo.lock
--- 2/Cargo.lock
+++ b/Cargo.lock
@@@ -266,7 -266,7 +266,7 @@@ dependencies = 
  
  [[package]]
  name = "cargo"
 -version = "0.41.0"
 +version = "0.42.0"
  dependencies = [
   "atty",
   "bytesize",
@@@ -276,7 -276,7 +276,7 @@@
   "clap",
   "core-foundation",
   "crates-io",
 - "crossbeam-utils 0.6.5",
 + "crossbeam-utils 0.7.0",
   "crypto-hash",
   "curl",
   "curl-sys",
@@@ -603,7 -603,6 +603,7 @@@ dependencies = 
   "serde_derive",
   "serde_json",
   "tempfile",
 + "tester",
   "winapi 0.3.8",
  ]
  
@@@ -666,7 -665,7 +666,7 @@@ checksum = "e7ca8a5221364ef15ce201e8ed2
  
  [[package]]
  name = "crates-io"
 -version = "0.29.0"
 +version = "0.30.0"
  dependencies = [
   "curl",
   "failure",
@@@ -783,17 -782,6 +783,17 @@@ dependencies = 
   "lazy_static 1.3.0",
  ]
  
 +[[package]]
 +name = "crossbeam-utils"
 +version = "0.7.0"
 +source = "registry+https://github.com/rust-lang/crates.io-index"
 +checksum = "ce446db02cdc3165b94ae73111e570793400d0794e46125cc4056c81cbb039f4"
 +dependencies = [
 + "autocfg",
 + "cfg-if",
 + "lazy_static 1.3.0",
 +]
 +
  [[package]]
  name = "crypto-hash"
  version = "0.3.1"
@@@ -3541,7 -3529,6 +3541,6 @@@ dependencies = 
   "rustc_metadata",
   "rustc_mir",
   "rustc_parse",
-  "rustc_plugin",
   "rustc_plugin_impl",
   "rustc_resolve",
   "rustc_save_analysis",
@@@ -3770,13 -3757,6 +3769,6 @@@ dependencies = 
   "syntax_pos",
  ]
  
- [[package]]
- name = "rustc_plugin"
- version = "0.0.0"
- dependencies = [
-  "rustc_plugin_impl",
- ]
- 
  [[package]]
  name = "rustc_plugin_impl"
  version = "0.0.0"
@@@ -3866,7 -3846,6 +3858,7 @@@ dependencies = 
   "log",
   "rustc",
   "rustc_data_structures",
 + "rustc_macros",
   "rustc_target",
   "smallvec 1.0.0",
   "syntax",
@@@ -4565,17 -4544,6 +4557,17 @@@ dependencies = 
   "term 0.0.0",
  ]
  
 +[[package]]
 +name = "tester"
 +version = "0.5.1"
 +source = "registry+https://github.com/rust-lang/crates.io-index"
 +checksum = "cd0d1044cb5ca390e9c93f8c35abd2c55484397dfd786f189321aa34605ee6ab"
 +dependencies = [
 + "getopts",
 + "libc",
 + "term 0.6.0",
 +]
 +
  [[package]]
  name = "textwrap"
  version = "0.11.0"