test: Fix run-fail testing and bring tests up to date

A typo in the Makefile was causing these to not run. Happily, a lot of these
tests pass, so un-xfailed.

src/test/run-fail/explicit-fail.rs

@@ -1,6 +1,3 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
 // error-pattern:explicit
 
 fn main() {

src/test/run-fail/expr-alt-fail.rs

@@ -1,4 +1,3 @@
-// xfail-stage0
 // error-pattern:explicit failure
 
 fn main() {

src/test/run-fail/expr-if-fail.rs

@@ -1,4 +1,3 @@
-// xfail-stage0
 // error-pattern:explicit failure
 
 fn main() {

src/test/run-fail/fail.rs

@@ -1,6 +1,3 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
 // error-pattern:1 == 2
 
 fn main() {

src/test/run-fail/non-exhaustive-match.rs

@@ -1,6 +1,3 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
 // -*- rust -*-
 
 // error-pattern:non-exhaustive match failure

src/test/run-fail/str-overrun.rs

@@ -1,6 +1,3 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
 // -*- rust -*-
 
 // error-pattern:bounds check

src/test/run-fail/trivial-message2.rs

@@ -1,4 +1,6 @@
 // xfail-stage0
+// xfail-stage1
+// xfail-stage2
 /*
   This program should hang on the r <- po line.
  */

src/test/run-fail/vec-overrun.rs

@@ -1,6 +1,3 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
 // -*- rust -*-
 
 // error-pattern:bounds check

src/test/run-fail/vec-underrun.rs

@@ -1,6 +1,3 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
 // -*- rust -*-
 
 // error-pattern:bounds check