[compiler-rt] Add API to temporalily disable usage of ASAN's fake stack (PR #160135)

[Vitaly Buka via llvm-commits]

================
@@ -179,6 +185,7 @@ class AsanThread {
   DTLS *dtls_;
 
   FakeStack *fake_stack_;
+  bool fake_stack_enabled_;
----------------
vitalybuka wrote:

please make it a counter

https://github.com/llvm/llvm-project/pull/160135