Fix Windows buildbot failure after rev 243301
Fix Windows buildbot failure after rev 243301

Summary:
- Visual Studio doesn't support "list initialization inside member initializer list"
- Call inner struct constructor explicitly

Reviewers:
enrico
Subscribers:
lldb-commits

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@243332 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,apple/swift-lldb