[cfi] Reset i-cache after copying code in test.
[cfi] Reset i-cache after copying code in test.

Fixes intermittent crashes on Android.
Also add PROT_READ to the code mapping for no real reason.

git-svn-id: c199f293c43da69278bea8e88f92242bf3aa95f7@335943 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt,llvm-mirror/compiler-rt