rust: Re-enable host address sanitizer.

Our toolchain supports a flag "-Z external-clangrt=true" which prevents
rustc from emitting a missing dependency to librust-dev_rt. Instead, we
link in libclang_rt.

Bug: 304507701
Bug: 324826914
Test: SANITIZE_HOST=address m aconfig
Change-Id: I8020c550b7a922c80620f61c22e01848a4f4a349

rust/sanitize.go

@@ -56,6 +56,8 @@ type SanitizeProperties struct {
 }
 
 var fuzzerFlags = []string{
+	"-Z external-clangrt=true",
+
 	"-C passes='sancov-module'",
 
 	"--cfg fuzzing",
@@ -73,11 +75,13 @@ var fuzzerFlags = []string{
 }
 
 var asanFlags = []string{
+	"-Z external-clangrt=true",
 	"-Z sanitizer=address",
 }
 
 // See cc/sanitize.go's hwasanGlobalOptions for global hwasan options.
 var hwasanFlags = []string{
+	"-Z external-clangrt=true",
 	"-Z sanitizer=hwaddress",
 	"-C target-feature=+tagged-globals",
 
@@ -203,11 +207,6 @@ func (sanitize *sanitize) begin(ctx BaseModuleContext) {
 		s.Address = nil
 	}
 
-	// TODO: Remove once b/304507701 is resolved
-	if Bool(s.Address) && ctx.Host() {
-		s.Address = nil
-	}
-
 	// Memtag_heap is only implemented on AArch64.
 	if ctx.Arch().ArchType != android.Arm64 || !ctx.Os().Bionic() {
 		s.Memtag_heap = nil