[lldbsuite, windows] Mark tests as XFAIL on Windows or skip them

Summary:
1) Several tests that are flakey on windows fail the run even if they are marked as expected to be flakey. This is because they fail frequently enough that even a retry won't help
2) Skip several tests on Windows that will occasionally hang rather than failing or exiting. This is causing the entire test suite to hang

Reviewers: asmith, labath, zturner

Reviewed By: zturner

Differential Revision: https://reviews.llvm.org/D50198

llvm-svn: 338769