Reduce swiftshader logspam on exit

It might be a legacy swiftshader bug because it does not happen on
SwANGLE or hardware GPU.

So let's not spam errors.

Bug: 284523053
Change-Id: I276686cde2defed2173c0cdd64a649fbe70d7f1d
diff --git a/host/gl/ReadbackWorkerGl.cpp b/host/gl/ReadbackWorkerGl.cpp
index 98bc9d4..7b02f6c 100644
--- a/host/gl/ReadbackWorkerGl.cpp
+++ b/host/gl/ReadbackWorkerGl.cpp
@@ -47,13 +47,7 @@
 }
 
 ReadbackWorkerGl::~ReadbackWorkerGl() {
-    s_gles2.glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
-    s_gles2.glBindBuffer(GL_COPY_READ_BUFFER, 0);
-    for (auto& r : mTrackedDisplays) {
-        s_gles2.glDeleteBuffers(r.second.mBuffers.size(), &r.second.mBuffers[0]);
-    }
-
-    mFlushSurface->getContextHelper()->teardownContext();
+    // Context not available on exit
 }
 
 void ReadbackWorkerGl::initReadbackForDisplay(uint32_t displayId, uint32_t w, uint32_t h) {