rust: Support MTE memtag_heap sanitizer

This CL adds support for the MTE memtag_heap sanitizer. This is
controlled via inclusion of an ELF note.

Bug: 170672854
Test: Heap MTE-enabled Rust test binary triggers MTE
Change-Id: I2619818785e86a94667d02b30d102c83456b7925
diff --git a/rust/rust_test.go b/rust/rust_test.go
index 80f693e..fe55d5f 100644
--- a/rust/rust_test.go
+++ b/rust/rust_test.go
@@ -442,3 +442,10 @@
 	m.Output("libwaldo.dylib.so.bloaty.csv")
 	m.Output("stripped/libwaldo.dylib.so.bloaty.csv")
 }
+
+func assertString(t *testing.T, got, expected string) {
+	t.Helper()
+	if got != expected {
+		t.Errorf("expected %q got %q", expected, got)
+	}
+}