[KMSAN] Enable -msan-handle-asm-conservative by default

This change enables conservative assembly instrumentation in KMSAN builds
by default.
It's still possible to disable it with -msan-handle-asm-conservative=0
if something breaks. It's now impossible to enable conservative
instrumentation for userspace builds, but it's not used anyway.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@348112 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed