[asan] further speedup use-after-return: simplify deallocation of fake frames. ~ 20% speedup.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190852 91177308-0d34-0410-b5e6-96231b3b80d8
[ASan] Link tests with -pie if ASan runtime uses zero-base shadow

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@190853 91177308-0d34-0410-b5e6-96231b3b80d8