Auto merge of #36335 - mcarton:compiletest, r=GuillaumeGomez

Fix ICE test in compiletest fail-tests

While working on Clippy which uses *compiletest*, I noticed that as long as all expected error are found, *compile-fail* tests will be marked *ok* even if there is an ICE. One function seems to have not been updated with JSON errors because ICEs are now reported like this:
```json
{"message":"../src/librustc/ty/context.rs:161: Attempted to intern `_` which contains inference types/regions in the global type context","code":null,"level":"error: internal compiler error","spans":[],"children":[],"rendered":null}
```
I don't think I can add a test for that.

I guess:
r? @nikomatsakis

src/test/compile-fail/issue-31109.rs

@@ -11,5 +11,7 @@
 fn main() {
     // FIXME(#31407) this error should go away, but in the meantime we test that it
     // is accompanied by a somewhat useful error message.
-    let _: f64 = 1234567890123456789012345678901234567890e-340; //~ ERROR could not evaluate float
+    let _: f64 = 1234567890123456789012345678901234567890e-340;
+    //~^ ERROR constant evaluation error
+    //~| unimplemented constant expression: could not evaluate float literal
 }