[Analysis] Make test require asserts

This is a hacky fix to get the bots green, because just reverting the
original commit causes more failures. This should be replaced with a
proper fix by the author.

Author: smeenai

clang/test/Analysis/builtin_signbit.cpp

@@ -5,6 +5,7 @@
 // RUN:   -O0 %s -o - | FileCheck %s --check-prefixes=CHECK-BE64
 // RUN: %clang -target powerpc64le-linux-gnu -emit-llvm -S -mabi=ibmlongdouble \
 // RUN:   -O0 %s -o - | FileCheck %s --check-prefixes=CHECK-LE
+// REQUIRES: asserts
 
 bool b;
 double d = -1.0;