auto merge of #12055 : dguenther/rust/tidy_test, r=alexcrichton

This PR extends the tidy formatting check to rust files in the test folder. To facilitate this, a few flags were added to tidy:

* `xfail-tidy-cr` - Disables the check for CR characters for all following lines in the file
* `xfail-tidy-tab` - Disables the check for tab characters for all following lines in the file
* `xfail-tidy-linelength` - Disables the line length check for all following lines in the file

Checks should not have to be disabled often. I disabled line length checks in `debug-info` tests that use `debugger:` checks, but aside from that, there were relatively few exclusions. Running tidy on all the tests does slow down the formatting check, so it may be worth investigating further optimization.

cc #4534

1 files changed, 4 insertions, 1 deletions

diff --git a/src/test/compile-fail/extenv-not-defined-default.rs b/src/test/compile-fail/extenv-not-defined-default.rs
index 24e447eec6d..d99d4dc33a2 100644
--- a/src/test/compile-fail/extenv-not-defined-default.rs
+++ b/src/test/compile-fail/extenv-not-defined-default.rs
@@ -8,4 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-fn main() { env!("__HOPEFULLY_NOT_DEFINED__"); } //~ ERROR: environment variable `__HOPEFULLY_NOT_DEFINED__` not defined
+fn main() {
+    env!("__HOPEFULLY_NOT_DEFINED__");
+    //~^ ERROR: environment variable `__HOPEFULLY_NOT_DEFINED__` not defined
+}