test: Un-xfail some compile-fail tests

Changed a few error patterns to match rustc's errors where it seemed
reasonable.

src/test/compile-fail/bad-alt.rs

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

src/test/compile-fail/bad-env-capture.rs

@@ -1,5 +1,3 @@
-// xfail-stage0
-// xfail-stage1
 // error-pattern: attempted dynamic environment-capture
 fn foo() {
   let int x;

src/test/compile-fail/bad-env-capture2.rs

@@ -1,5 +1,3 @@
-// xfail-stage0
-// xfail-stage1
 // error-pattern: attempted dynamic environment-capture
 fn foo(int x) {
   fn bar() {

src/test/compile-fail/bad-env-capture3.rs

@@ -1,5 +1,3 @@
-// xfail-stage0
-// xfail-stage1
 // error-pattern: attempted dynamic environment-capture
 obj foo(int x) {
     fn mth() {

src/test/compile-fail/bad-recv.rs

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

src/test/compile-fail/bad-send.rs

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

src/test/compile-fail/no-self-dispatch.rs

@@ -1,7 +1,4 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
-// error-pattern: unresolved identifier
+// error-pattern: unresolved name
 obj oT() {
   fn get() -> int {
     ret 3;

src/test/compile-fail/unbalanced-comment.rs

@@ -1,9 +1,6 @@
-// xfail-stage0
-// xfail-stage1
-// xfail-stage2
 // -*- rust -*-
 
-// error-pattern: token
+// error-pattern: unterminated block comment
 
 /*
  * This is an un-balanced /* multi-line comment.