Change the NOOP fallback, in CompiledFont, to return a TypedArray

In PR 20367 the `CompiledFont.prototype.getPathJs` method was changed to return TypedArray data, however the `NOOP` fallback was (likely accidentally) left an empty string.
The compilation of font-paths in PR 20346 was then implemented such that an empty string just happened to be ignored silently, however the assert added in PR 20894 allowed me to spot this return value inconsistency.

*Please note:* Since this only applies to missing or broken glyphs, that wouldn't be rendered anyway, this doesn't show up in reference tests.

Author: Snuffleupagus

src/core/font_renderer.js

@@ -20,6 +20,7 @@ import {
   FeatureTest,
   FONT_IDENTITY_MATRIX,
   FormatError,
+  shadow,
   unreachable,
   Util,
   warn,
@@ -736,8 +737,6 @@ function compileCharString(charStringCode, cmds, font, glyphId) {
   parse(charStringCode);
 }
 
-const NOOP = "";
-
 class Commands {
   cmds = [];
 
@@ -774,12 +773,13 @@ class Commands {
   }
 
   getPath() {
-    if (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) {
+    if (
+      (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
+      FeatureTest.isFloat16ArraySupported
+    ) {
       return new Float16Array(this.cmds);
     }
-    return new (
-      FeatureTest.isFloat16ArraySupported ? Float16Array : Float32Array
-    )(this.cmds);
+    return new Float32Array(this.cmds);
   }
 }
 
@@ -797,6 +797,17 @@ class CompiledFont {
     this.compiledCharCodeToGlyphId = Object.create(null);
   }
 
+  static get NOOP() {
+    return shadow(
+      this,
+      "NOOP",
+      (typeof PDFJSDev !== "undefined" && PDFJSDev.test("MOZCENTRAL")) ||
+        FeatureTest.isFloat16ArraySupported
+        ? new Float16Array(0)
+        : new Float32Array(0)
+    );
+  }
+
   getPathJs(unicode) {
     const { charCode, glyphId } = lookupCmap(this.cmap, unicode);
     let fn = this.compiledGlyphs[glyphId],
@@ -805,7 +816,7 @@ class CompiledFont {
       try {
         fn = this.compileGlyph(this.glyphs[glyphId], glyphId);
       } catch (ex) {
-        fn = NOOP; // Avoid attempting to re-compile a corrupt glyph.
+        fn = CompiledFont.NOOP; // Avoid attempting to re-compile a corrupt glyph.
 
         compileEx = ex;
       }
@@ -821,7 +832,7 @@ class CompiledFont {
 
   compileGlyph(code, glyphId) {
     if (!code?.length || code[0] === 14) {
-      return NOOP;
+      return CompiledFont.NOOP;
     }
 
     let fontMatrix = this.fontMatrix;