[llvm] [ASAN] Adjust asan instrumented GlobalVariable size to not include redzone (PR #66666)

[via llvm-commits]

b-sumner wrote:

The reason this is a problem is that AMD language runtimes provide queries for the size of device global symbols, and functions to copy data to and from device global variables.  This works fine when the ELF size reflects the actual size of the variable.  But when it reflects the instrumented size of the variable then it causes problems, e.g. reading from the poisoned redzone.

https://github.com/llvm/llvm-project/pull/66666