Add xfailed test cases

Author: catamorphism

src/test/run-pass/issue-3121.rs

@@ -0,0 +1,18 @@
+// xfail-test
+enum side { mayo, catsup, vinegar }
+enum order { hamburger, fries(side), shake }
+enum meal { to_go(order), for_here(order) }
+
+fn foo(m: @meal, cond: bool) {
+    match *m {
+      to_go(_) => { }
+      for_here(_) if cond => {}
+      for_here(hamburger) => {}
+      for_here(fries(_s)) => {}
+      for_here(shake) => {}
+    }
+}
+
+fn main() {
+    foo(@for_here(hamburger), true)
+}

src/test/run-pass/issue-3895.rs

@@ -0,0 +1,9 @@
+// xfail-test
+fn main() {
+    enum State { BadChar, BadSyntax }
+    
+    match BadChar {
+        _ if true => BadChar,
+        BadChar | BadSyntax => fail ,
+    };
+}