Due to differences in compiler versions and optimization levels,
std::floor treats snan differently, as does std::ceil and std::trunc.
So the implementation of some instructions is sometimes inconsistent
with the physical machine. We add extra processing to them.

Besides, fix Loong64Debugger::Debug error in simulator, IsTrap
returns true only if break is encountered.

Change-Id: I240d91ed658645a2453162107b6dd172735fbfef
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3661259Reviewed-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/main@{#80714}