make expect_stdout work on Node.js 0.12 (#1623)

That particular version of Node.js has messed up error messages, so provide a version-specific workaround.

Also fixed an formatting issue which would cause `expect_stdout` to fail if error message contains excerpts of input.

Apply `expect_stdout` to more applicable tests.

test/compress/loops.js

@@ -166,6 +166,7 @@ keep_collapse_const_in_own_block_scope: {
             console.log(i);
         console.log(c);
     }
+    expect_stdout: true
 }
 
 keep_collapse_const_in_own_block_scope_2: {
@@ -186,6 +187,7 @@ keep_collapse_const_in_own_block_scope_2: {
             console.log(i);
         console.log(c);
     }
+    expect_stdout: true
 }
 
 evaluate: {