The BumpPool of VkStream is not freeAll'ed

Original change from: kyoungwon.kim@bytedance.com at aosp/3310239
Moving the change into gfxstream and codegen.

The issue was found by pengzejie@bytedance.com.

Note that vkReadStream's BumpPool is effectively `freeAll`'ed by
`clearPool` calls. The same call for vkStream is not being called
while alloc is called here and there.

Reviewed-by: Marcin Radomski <dextero@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33018>

src/gfxstream/codegen/scripts/cereal/decoder.py

@@ -963,6 +963,7 @@ size_t VkDecoder::Impl::decode(void* buf, size_t len, IOStream* ioStream,
         self.cgen.endBlock() # switch stmt
 
         self.cgen.stmt("ptr += packetLen")
+        self.cgen.stmt("vkStream->clearPool()")
         self.cgen.endBlock() # while loop
 
         self.cgen.beginIf("m_forSnapshotLoad")