Unignore some working emscripten tests

Author: brson

src/test/run-fail/run-unexported-tests.rs

@@ -12,7 +12,6 @@
 // compile-flags:--test
 // check-stdout
 // ignore-pretty: does not work well with `--test`
-// ignore-emscripten Needs threads.
 
 mod m {
     pub fn exported() {}

src/test/run-pass/issue-16597.rs

@@ -10,7 +10,6 @@
 
 // compile-flags:--test
 // ignore-pretty turns out the pretty-printer doesn't handle gensym'd things...
-// ignore-emscripten
 
 mod tests {
     use super::*;

src/test/run-pass/issue-20823.rs

@@ -10,7 +10,6 @@
 
 // compile-flags: --test
 // no-pretty-expanded
-// ignore-emscripten
 
 #![deny(unstable)]
 

src/test/run-pass/issue-29663.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 // write_volatile causes an LLVM assert with composite types
-// ignore-emscripten write_volatile doesn't work on arrays of structs?
 
 #![feature(volatile)]
 use std::ptr::{read_volatile, write_volatile};

src/test/run-pass/packed-struct-vec.rs

@@ -7,7 +7,6 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-// ignore-emscripten Right side of comparison is screwed up. No idea how.
 
 use std::mem;
 

src/test/run-pass/test-fn-signature-verification-for-explicit-return-type.rs

@@ -7,7 +7,6 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-// ignore-emscripten needs threads?
 
 #![feature(test)]
 

src/test/run-pass/test-should-fail-good-message.rs

@@ -10,7 +10,6 @@
 
 // compile-flags: --test
 // ignore-pretty: does not work well with `--test`
-// ignore-emscripten needs threads?
 
 #[test]
 #[should_panic(expected = "foo")]