[compiler-rt] [hwasan] Fix a possible null dereference problem (PR #77737)

[Wu Yingcong via llvm-commits]

yingcong-wu wrote:

Hi, I don't have any ideas on how to build a test case for this, could you please give some direction? 
Or can we land this patch without a test?

https://github.com/llvm/llvm-project/pull/77737