Handle static unwinder in ltoDepsMutator

The implementation before libraryDependencyTag was added failed to
treat the libgcc_unwind dependency as a static library when traversing
dependencies for LTO because it didn't handle staticUnwinderDepTag.

Bug: 162437057
Test: m checkbuild
Change-Id: Iccc96c0daa0379f51eb975c51fd5e8c507a0daba

cc/lto.go

@@ -152,9 +152,7 @@ func ltoDepsMutator(mctx android.TopDownMutatorContext) {
 
 			// Do not recurse down non-static dependencies
 			if isLibTag {
-				// TODO(ccross): the staticUnwinder check is there to maintain existing behavior
-				//   when adding libraryDependencyTag and should be removed.
-				if !libTag.static() || libTag.staticUnwinder {
+				if !libTag.static() {
 					return false
 				}
 			} else {