Random HWASan cleanups.

Makes CtsBionicTestCases pass under HWASan.

Bug: 193568145
Test: CtsBionicTestCases
Change-Id: I38ee8a8508827c0ffee61ce33bb8c6a3f40388c9
diff --git a/tests/dlext_test.cpp b/tests/dlext_test.cpp
index e3caf0e..47214b8 100644
--- a/tests/dlext_test.cpp
+++ b/tests/dlext_test.cpp
@@ -714,7 +714,7 @@
 }
 
 std::string DlExtRelroSharingTest::FindMappingName(void* ptr) {
-  uint64_t addr = reinterpret_cast<uint64_t>(ptr);
+  uint64_t addr = reinterpret_cast<uint64_t>(untag_address(ptr));
   std::string found_name = "<not found>";
 
   EXPECT_TRUE(android::procinfo::ReadMapFile("/proc/self/maps",