Limit propagating san config of shared to fuzzer

Prior to refactoring the sanitizers to use transition mutators, only
fuzzer sanitizer propagated configuration to shared dependencies
https://android-review.googlesource.com/c/platform/build/soong/+/2123434/9/cc/sanitize.go#b1365
However, this expanded to include TSAN in the refactoring
https://android-review.googlesource.com/c/platform/build/soong/+/2123434/9/cc/sanitize.go#1068.

Fortunately, TSAN is never enabled via Android.bp files in AOSP, so
there was no regression, but we should restore to the prevous state.

Test: go tests
Change-Id: I1a5ad8d033f7a9b4f7578393a2eac7c9362ab6f7