This just eliminates -enable-sil-ownership from all target-swift-frontend and
target-swift-emit-silgen RUN lines. Both of those now include
enable-sil-ownership in their expansion.
The sil files have been left alone and mandatory inlining is still only being
applied to SIL without ownership. That is coming in a forthcoming commit.
rdar://31521023
This will generate significantly better code if a generic optional is compared against nil.
In a generic function this ended up with a call to the == function. Now, due to mandatory inlining, it boils down to a switch_enum.
