Implement ParseExportDeclaration per latest ES6 spec draft

test/mjsunit/harmony/module-parsing.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --harmony-modules
 
 // Check that import/export declarations are rejected in eval or local scope.
-assertThrows("export x;", SyntaxError);
 assertThrows("export let x;", SyntaxError);
 assertThrows("import x from 'http://url';", SyntaxError);
 
-assertThrows("{ export x; }", SyntaxError);
 assertThrows("{ export let x; }", SyntaxError);
 assertThrows("{ import x from 'http://url'; }", SyntaxError);
 
-assertThrows("function f() { export x; }", SyntaxError);
 assertThrows("function f() { export let x; }", SyntaxError);
 assertThrows("function f() { import x from 'http://url'; }", SyntaxError);
 
-assertThrows("function f() { { export x; } }", SyntaxError);
 assertThrows("function f() { { export let x; } }", SyntaxError);
 assertThrows("function f() { { import x from 'http://url'; } }", SyntaxError);