fortify: allow diagnostics without run-time checks (attempt #2)

In configs like ASAN, we can't use _chk functions. This CL builds off of
previous work to allow us to still emit diagnostics in conditions like
these.

Wasn't 100% sure what a good test story would look like here. Opinions
appreciated.

Bug: 141267932
Test: checkbuild on internal-master. TreeHugger for x86_64.
Change-Id: I65da9ecc9903d51a09f740e38ab413b9beaeed88
diff --git a/tests/Android.bp b/tests/Android.bp
index 1755053..ee4f02e 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -312,26 +312,20 @@
     },
 }
 
-// If building this fails, then we have both FORTIFY and ASAN enabled, which
-// isn't desirable. (Ideally, we'd emit FORTIFY diagnostics even with ASAN
-// enabled, but that's not a reality today.) This is meant to be otherwise
-// unused.
-cc_test_library {
-    name: "fortify_disabled_for_asan",
+// Ensures that FORTIFY checks aren't run when ASAN is on.
+cc_test {
+    name: "bionic-fortify-runtime-asan-test",
     defaults: [
         "bionic_clang_fortify_tests_w_flags",
     ],
     cflags: [
         "-Werror",
         "-D_FORTIFY_SOURCE=2",
-        // "sanitize: address" doesn't work on platforms where libasan isn't
-        // enabled. Since the intent is just to build this, we can get away with
-        // passing this flag on its own.
-        "-fsanitize=address",
     ],
-    // Ignore that we don't have ASAN symbols linked in.
-    allow_undefined_symbols: true,
-    srcs: ["clang_fortify_tests.cpp"],
+    sanitize: {
+        address: true,
+    },
+    srcs: ["clang_fortify_asan.cpp"],
 }
 
 // Ensure we don't use FORTIFY'ed functions with the static analyzer/clang-tidy: