When kSpeculationPoisonRegister is a7, the test
TestFastJSWasmCall_MultipleArgs failed.

Besides, delete an unuse member named table_entry_size_.

Change-Id: Ic2c8b68d50c02dca7c41520ceb217fec33fe8cc4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2644539Reviewed-by: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn>
Auto-Submit: Liu yu <liuyu@loongson.cn>
Cr-Commit-Position: refs/heads/master@{#72245}