[hwasan] Fix stack-uar.c after rCRT345110
Set -fno-discard-value-names so that the frame description string contains the variable name.
// Tests use-after-return detection and reporting.
-// RUN: %clang_hwasan -O0 %s -o %t && not %run %t 2>&1 | FileCheck %s
+// RUN: %clang_hwasan -O0 -fno-discard-value-names %s -o %t && not %run %t 2>&1 | FileCheck %s
// REQUIRES: stable-runtime
