Attributes: Simplify the option val hook; backport a test from master

The hook is still defined; not using it could cause issues in IE<11.
Backport the test from the master branch.

Also, IE10 no longer throws when value not set but it still doesn't trim the
value. IE11 has all those issues fixed; support comments are updated.

(cherry-picked from f6302b0b53d61dfe1adbfaf6612be5cbced5bbc1)

Fixes gh-1902
Closes gh-1901

src/attributes/val.js

@@ -72,12 +72,9 @@ jQuery.extend({
 	valHooks: {
 		option: {
 			get: function( elem ) {
-				var val = jQuery.find.attr( elem, "value" );
-				return val != null ?
-					val :
-					// Support: IE10-11+
-					// option.text throws exceptions (#14686, #14858)
-					jQuery.trim( jQuery.text( elem ) );
+				// Support: IE<11
+				// option.value not trimmed (#14858)
+				return jQuery.trim( elem.value );
 			}
 		},
 		select: {

test/unit/attributes.js

@@ -1459,6 +1459,11 @@ test( "should not throw at $(option).val() (#14686)", 1, function() {
 	}
 });
 
+test( "option value not trimmed when setting via parent select", function() {
+	expect( 1 );
+	equal( jQuery( "<select><option> 2</option></select>" ).val( "2" ).val(), "2" );
+});
+
 test( "Insignificant white space returned for $(option).val() (#14858)", function() {
 	expect ( 3 );