[llvm] build: make sanitizer builds use optimized tablegen (PR #156784)

[Florian Mayer via llvm-commits]

fmayer wrote:

> If it's with LLVM_OPTIMIZED_TABLEGEN only, then LGTM
> 
> We still want to be able to sanitize TABLEGEN as well

I realized the commit message makes it easy to confuse this. Please change to something on Ike "respect LLVM_OPTIMIZED_TABLEGEN for sanitizers".

https://github.com/llvm/llvm-project/pull/156784