detach -> release

The C++ standard library uses the name "release" for the operation we call "detach".

Rewriting each "detach(" to "release(" brings us a step closer to using standard library types directly (e.g. std::unique_ptr instead of SkAutoTDelete).

This was a fairly blind transformation.  There may have been unintentional conversions in here, but it's probably for the best to have everything uniformly say "release".

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1809733002

Review URL: https://codereview.chromium.org/1809733002
diff --git a/samplecode/SampleApp.cpp b/samplecode/SampleApp.cpp
index 6d5f647..7212223 100644
--- a/samplecode/SampleApp.cpp
+++ b/samplecode/SampleApp.cpp
@@ -261,7 +261,7 @@
             fCurIntf = nullptr;
             SkDebugf("Failed to setup 3D");
 
-            win->detach();
+            win->release();
         }
 #endif // SK_SUPPORT_GPU
         // call windowSizeChanged to create the render target
@@ -283,7 +283,7 @@
         SkSafeUnref(fCurRenderTarget);
         fCurRenderTarget = nullptr;
 #endif
-        win->detach();
+        win->release();
         fBackend = kNone_BackEndType;
     }