Revert "surfaceflinger: clear HWC layers in Layer::onRemoved"

Causing failures due to lack of clearHwcLayers in git_master and few 
other branches/builds. Looks like clearHwcLayers needs USE_HWC2 
to be defined, seems to be not defined in few branches/builds?

This reverts commit 06837418fe9fb0c6deeab7d62ac5bf65c7bb2b98.

Change-Id: Ic0e3a99b45543503d5fa8a90f3569764ebe922e3
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 89ba2ee..06a0765 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -296,9 +296,6 @@
     }
 
     mSurfaceFlingerConsumer->abandon();
-
-    clearHwcLayers();
-
     for (const auto& child : mCurrentChildren) {
         child->onRemoved();
     }