Fix issues with xss linters

Improve accuracy of javascript-escape linter: Previously this would
match on FOOescape() and FOO.escape calls, but neither are the global
escape function we are worried about.

The regex probably isn't 100% accurate; there may be still false
positives (javascript allows a large range of characters in identifiers,
some of which may not be covered by [\w.$]). The main thing is to avoid
false negatives here though - this will definitely catch any use of
`escape()` or `window.escape()`.

Also remove javascript-interpolate lint - this was deemed unecessary.
StringUtils.interpolate is not in fact safe (it does no html escaping),
so the results of this lint are misleading.

common/lib/xmodule/xmodule/js/src/capa/schematic.js

@@ -2810,7 +2810,7 @@ schematic = (function() {
 			    // for each requested freq, interpolate response value
 			    for (var k = 1; k < flist.length; k++) {
 				var f = flist[k];
-				var v = interpolate(f,x_values,values);  //xss-lint: disable=javascript-interpolate
+				var v = interpolate(f,x_values,values);
 				// convert to dB
 				fvlist.push([f,v == undefined ? 'undefined' : 20.0 * Math.log(v)/Math.LN10]);
 			    }
@@ -2932,7 +2932,7 @@ schematic = (function() {
 				    // for each requested time, interpolate waveform value
 				    for (var k = 1; k < tlist.length; k++) {
 					var t = tlist[k];
-					var v = interpolate(t,times,values); // xss-lint: disable=javascript-interpolate
+					var v = interpolate(t,times,values);
 					tvlist.push([t,v == undefined ? 'undefined' : v]);
 				    }
 				    // save results as list of [t,value] pairs
@@ -2978,7 +2978,7 @@ schematic = (function() {
 
 	// t is the time at which we want a value
 	// times is a list of timepoints from the simulation
-	function interpolate(t,times,values) { // xss-lint: disable=javascript-interpolate
+	function interpolate(t,times,values) {
 	    if (values == undefined) return undefined;
 
 	    for (var i = 0; i < times.length; i++)
@@ -5219,7 +5219,7 @@ schematic = (function() {
 	}
 	Wire.prototype = new Component();
 	Wire.prototype.constructor = Wire;
-    
+
         Wire.prototype.toString = function() {
 	    return edx.StringUtils.interpolate(
 		'<Wire ({x},{y}) ({x_plus_dx},{y_plus_dy})>',
@@ -5348,7 +5348,7 @@ schematic = (function() {
 		    y: this.y
 		});
 	}
-    
+
 	Ground.prototype.draw = function(c) {
 	    Component.prototype.draw.call(this,c);   // give superclass a shot
 	    this.draw_line(c,0,0,0,8);

common/lib/xmodule/xmodule/js/src/sequence/display.js

@@ -329,7 +329,6 @@
                 this.render(newPosition);
             } else {
                 alertTemplate = gettext('Sequence error! Cannot navigate to %(tab_name)s in the current SequenceModule. Please contact the course staff.');  // eslint-disable-line max-len
-                // xss-lint: disable=javascript-interpolate
                 alertText = interpolate(alertTemplate, {
                     tab_name: newPosition
                 }, true);

common/lib/xmodule/xmodule/js/src/video/06_video_progress_slider.js

@@ -329,7 +329,6 @@ function() {
                     msg = ngettext('%(value)s second', '%(value)s seconds', value);
                     break;
                 }
-                // xss-lint: disable=javascript-interpolate
                 return interpolate(msg, {value: value}, true);
             };