Reverts "[Impeller] Enable depth buffer clipping & Stencil-then-Cover path rendering. (#51209)" (#51217)

Reverts #51209
Initiated by: bdero
Reason for reverting: Golden breakages on [engine roll](flutter/flutter#144647) https://flutter-gold.skia.org/search?issue=144647&crs=github&patchsets=5&corpus=flutter
Original PR Author: bdero

Reviewed By: {jonahwilliams, chinmaygarde}

This change reverts the following previous change:
Original Description:
Turn the page, wash your hands.

Addresses the following issues:
* flutter/flutter#143077
* flutter/flutter#137714
* flutter/flutter#138460
* flutter/flutter#123671
* flutter/flutter#141961
* flutter/flutter#134432

Previous attempt:
- #50856
    - reverted with #51191
    - fixed with #51198

Author: auto-submit[bot]

impeller/entity/contents/content_context.h

@@ -408,7 +408,7 @@ class ContentContext {
   ///
   // TODO(bdero): Remove this setting once StC is fully de-risked
   //              https://github.com/flutter/flutter/issues/123671
-  static constexpr bool kEnableStencilThenCover = true;
+  static constexpr bool kEnableStencilThenCover = false;
 
 #if IMPELLER_ENABLE_3D
   std::shared_ptr<scene::SceneContext> GetSceneContext() const;