Reverts "[ios][platform_view] Use CAShapeLayer as the mask to avoid software rendering  (#53072)" (#53220)

Reverts: flutter/engine#53072
Initiated by: jason-simmons
Reason for reverting: compilation errors on iOS targets

```
FlutterPlatformViews_Internal.mm:277:10: error: ARC forbids explicit message send of 'dealloc'
  277 |   [super dealloc];
      |    ~~~~~ ^
 ```

(see https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8746006425774972161/+/u/build_ci_ios_debug_unopt_sim_flutter_testing_scenario_app_flutter_shell_platform_darwin_ios:ios_test_flutter/st
Original PR Author: hellohuanlin

Reviewed By: {cbracken, jonahwilliams}

This change reverts the following previous change:
This PR uses `CAShapeLayer` as the mask to avoid software rendering.

I kept `UIView` as the mask, so that we can measure just the improvement related to avoiding software rendering. This also allows me to land this change sooner. I created [a separate issue](https://github.com/flutter/flutter/issues/149212) to track removing UIView as the mask.

Note: the previous behavior seems to be incorrect (or at least not pixel perfect). This PR fixed it. See comments.

See design doc: https://docs.google.com/document/d/1TqG_N4GK_qctuk73Gk3zOdAiILUrwMqxoCMgroK_AeA/edit?resourcekey=0-jUiidfzIS642ngG2w9vSUA&tab=t.0

*List which issues are fixed by this PR. You must list at least one issue.*

Fixes https://github.com/flutter/flutter/issues/142813
Fixes https://github.com/flutter/flutter/issues/142830

*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
https://dart.googlesource.com/external/github.com/flutter/engine/+/40d7aaafee63a2b4b1503b783a530a8e9b54b8ef

DEPS

diff --git a/DEPS b/DEPS
index 700d184..df0a59f 100644
--- a/DEPS
+++ b/DEPS
@@ -280,7 +280,7 @@
 deps = {
   'engine/src': 'https://github.com/flutter/buildroot.git' + '@' + '9a4ba8138aed94000ac5070590a21030008903bb',
 
-  'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + '1314faf00cb9ab0234531dc63a281d07f1d861dc',
+  'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + '40d7aaafee63a2b4b1503b783a530a8e9b54b8ef',
 
   'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '1c692c7b715b1ea802fd9f747f117fc9dd8f331b',
 

commits.json

diff --git a/commits.json b/commits.json
index ff99a7a..ed758a1 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
-  "engine/src/flutter":"1314faf00cb9ab0234531dc63a281d07f1d861dc",
+  "engine/src/flutter":"40d7aaafee63a2b4b1503b783a530a8e9b54b8ef",
   "engine/src/flutter/third_party/dart":"1c692c7b715b1ea802fd9f747f117fc9dd8f331b",
   "flutter":"63daac2a51deb76ab13814260fc8ae9f8efc7451"
 }
\ No newline at end of file