[Windows] Convert GetLastError to std::error_code
[Windows] Convert GetLastError to std::error_code

Create a std::error_code from the result of GetLastError, which in turn
we can use to return an llvm::Error.

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@365390 91177308-0d34-0410-b5e6-96231b3b80d8

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