With BytecodeArray flushing the SFI->BytecodeArray pointer will become pseudo weak.
In order to avoid having to recompile (and potentially stack-overflow) on
deoptimization, we explicitly add strong references to any BytecodeArray's we
might deopt into into the DeoptimizationData, as such the BytecodeArrays won't
be flushed while there is optimized code referencing it.

BUG=v8:8395

Change-Id: If3336dfa9c17b7bccafdb73752c58dfa1f14a371
Reviewed-on: https://chromium-review.googlesource.com/c/1314579
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#57543}