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

cc/sanitize.go

@@ -171,6 +171,20 @@ func (t SanitizerType) registerMutators(ctx android.RegisterMutatorsContext) {
 	}
 }
 
+// shouldPropagateToSharedLibraryDeps returns whether a sanitizer type should propagate to share
+// dependencies. In most cases, sanitizers only propagate to static dependencies; however, some
+// sanitizers also must be enabled for shared libraries for linking.
+func (t SanitizerType) shouldPropagateToSharedLibraryDeps() bool {
+	switch t {
+	case Fuzzer:
+		// Typically, shared libs are not split. However, for fuzzer, we split even for shared libs
+		// because a library sanitized for fuzzer can't be linked from a library that isn't sanitized
+		// for fuzzer.
+		return true
+	default:
+		return false
+	}
+}
 func (*Module) SanitizerSupported(t SanitizerType) bool {
 	switch t {
 	case Asan:
@@ -1127,7 +1141,8 @@ func (s *sanitizerSplitMutator) IncomingTransition(ctx android.IncomingTransitio
 				return s.sanitizer.variationName()
 			}
 
-			if s.sanitizer == cfi || s.sanitizer == Hwasan || s.sanitizer == scs || s.sanitizer == Asan {
+			// Some sanitizers do not propagate to shared dependencies
+			if !s.sanitizer.shouldPropagateToSharedLibraryDeps() {
 				return ""
 			}
 		}