svg: do not rename inherited ListMixin.length= parameter

The docs are currently broken because the inherited docs contain
references to the parameter, `newLength`, but in the overridden
setters, there is no such parameter:

https://api.dart.dev/stable/3.4.4/dart-svg/NumberList/length.html

CoreLibraryReviewExempt: No-op.
Change-Id: I27388847109adeef66cdc1ef2e4faedeac5390d9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/372522
Commit-Queue: Sam Rawlins <srawlins@google.com>
Auto-Submit: Sam Rawlins <srawlins@google.com>
Reviewed-by: Srujan Gaddam <srujzs@google.com>

sdk/lib/svg/dart2js/svg_dart2js.dart

@@ -2065,7 +2065,7 @@ class LengthList extends JavaScriptObject
   // -- start List<Length> mixins.
   // Length is the element type.
 
-  set length(int value) {
+  set length(int newLength) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
@@ -2390,7 +2390,7 @@ class NumberList extends JavaScriptObject
   // -- start List<Number> mixins.
   // Number is the element type.
 
-  set length(int value) {
+  set length(int newLength) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
@@ -2873,7 +2873,7 @@ class StringList extends JavaScriptObject
   // -- start List<String> mixins.
   // String is the element type.
 
-  set length(int value) {
+  set length(int newLength) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }
 
@@ -3862,7 +3862,7 @@ class TransformList extends JavaScriptObject
   // -- start List<Transform> mixins.
   // Transform is the element type.
 
-  set length(int value) {
+  set length(int newLength) {
     throw new UnsupportedError("Cannot resize immutable List.");
   }