Add ICEs for rust#68091 and rust68092

Author: LunaBorowska

ices/68091.rs

@@ -0,0 +1,9 @@
+macro_rules! x {
+    ($($c:tt)*) => {
+        $($c)ö* {}
+    };
+}
+
+fn main() {
+    x!(if);
+}

ices/68092.rs

@@ -0,0 +1,9 @@
+macro_rules! x {
+    ($($c:tt)*) => {
+        $($c)ö*
+    };
+}
+
+fn main() {
+    x!(!);
+}