Update integration tests

Author: nrc

.travis.yml

@@ -31,15 +31,14 @@ matrix:
     - env: INTEGRATION=rand
     - env: INTEGRATION=rust-clippy
     - env: INTEGRATION=rust-semverver
+    - env: INTEGRATION=stdsimd
     - env: INTEGRATION=tempdir
   allow_failures:
-    # See: https://github.com/rust-lang-nursery/rustfmt/issues/2789
+    # Needs `edition = "Edition2018"` in rustfmt.toml
     - env: INTEGRATION=chalk
-    # PR sent
+    # Fails tests, don't know why
     - env: INTEGRATION=crater
-    # #2721
-    - env: INTEGRATION=rand
-    # Doesn't build
+    # Unknown
     - env: INTEGRATION=rust-clippy
     # See: https://github.com/rust-lang-nursery/rustfmt/issues/2787
     - env: INTEGRATION=stdsimd

rustfmt.toml

@@ -1,2 +1,3 @@
 error_on_line_overflow = true
 error_on_unformatted = true
+edition = "Edition2018"