Fix spread optimization on array literals with holes

Do not fold if the array literal has any holes as it's a syntax error to have holes (empty arg) if we're the spread happens to be a call arg.

PiperOrigin-RevId: 554601815

src/com/google/javascript/jscomp/PeepholeFoldConstants.java

@@ -1643,6 +1643,13 @@ private Node tryFoldSpread(Node spread) {
     Node parent = spread.getParent();
     Node child = spread.getOnlyChild();
     if (child.isArrayLit()) {
+      for (Node n = child.getFirstChild(); n != null; n = n.getNext()) {
+        if (n.getToken().equals(Token.EMPTY)) {
+          // Do not fold if the array literal has any holes as it's a syntax error to have holes
+          // (empty arg) if the spread happens to be a call arg
+          return spread;
+        }
+      }
       parent.addChildrenAfter(child.removeChildren(), spread);
       spread.detach();
       reportChangeToEnclosingScope(parent);

test/com/google/javascript/jscomp/PeepholeFoldConstantsTest.java

@@ -1412,6 +1412,7 @@ public void testFoldArraySpread() {
   @Test
   public void testFoldArrayLitSpreadInArg() {
     test("foo(...[0], 1)", "foo(0, 1)");
+    testSame("foo(...[,,,,\"foo\"], 1)");
     testSame("foo(...(false ? [0] : [1]))"); // other opts need to fold the ternery first
   }