Add a test to check that inline const is in required_consts

tests/ui/inline-const/required-const.rs

@@ -0,0 +1,13 @@
+// build-fail
+// compile-flags: -Zmir-opt-level=3
+#![feature(inline_const)]
+
+fn foo<T>() {
+    if false {
+        const { panic!() } //~ ERROR E0080
+    }
+}
+
+fn main() {
+    foo::<i32>();
+}

tests/ui/inline-const/required-const.stderr

@@ -0,0 +1,11 @@
+error[E0080]: evaluation of `foo::<i32>::{constant#0}` failed
+  --> $DIR/required-const.rs:7:17
+   |
+LL |         const { panic!() }
+   |                 ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/required-const.rs:7:17
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0080`.