scudo: Update TLS_SLOT_SANITIZER value.

Android now allocates only 8 fixed TLS slots. Somehow we were getting away
with using a non-existent slot until now, but in some cases the TLS slots
were being placed at the end of a page, which led to a segfault at startup.

Differential Revision:

git-svn-id: 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/scudo/standalone/linux.h b/lib/scudo/standalone/linux.h
index 92c9eb5..c8e4148 100644
--- a/lib/scudo/standalone/linux.h
+++ b/lib/scudo/standalone/linux.h
@@ -55,7 +55,7 @@
 // The Android Bionic team has allocated a TLS slot for sanitizers starting
 // with Q, given that Android currently doesn't support ELF TLS. It is used to
 // store sanitizer thread specific data.
-static const int TLS_SLOT_SANITIZER = 8; // TODO(kostyak): 6 for Q!!
+static const int TLS_SLOT_SANITIZER = 6;
 ALWAYS_INLINE uptr *getAndroidTlsPtr() {
   return reinterpret_cast<uptr *>(&__get_tls()[TLS_SLOT_SANITIZER]);