[MWF] Partially implement Help.ShowHelp
Test connection reuse.
Allow stream reuse when InputStream has been disposed.
If InputStream is disposed FlushInput now sets it to null so a new one can be created.
File URI's without a host are not UNC paths on Windows.

NUnit breaks when these URI's are treated as UNC paths, so I have no way of
running the tests on Windows without this change to see if it broke anything.
Not all URI tests pass, but the ones that fail seem unrelated to my change.

On Unix, the tests all work, but of course on Unix this is a no-op.

This commit licensed as MIT/X11.
[MWF] Display visual feedback on pressed button (#23869)

When a button is pressed the image and the text needs to be rendered one
pixel to the right and to the bottom so that there is some visual
feedback of the button press. Previously this was only the case if
TextImageRelation was set to Overlay.
[MWF] Improve ellipsis handling

- Don't subtract room for ellipsis. Ellipsis should be
  handled by the renderer so we shouldn't reserve space for it.
  Otherwise we end up not getting ellipsis (because the renderer
  thinks there is enough space available), or we don't use up the
  available space.
- Don't allow text to go below button if we want to show ellipsis.
Add/update missing bits in order to support MVC5.2.
Add ClientDisconnectedToken property to HttpResponseBase and Wrapper as default None
Re-apply the patch, there isa  fix for it
Revert incorrect changes from commit 950d9c8a567273c3363f43cee454f2b95a9f5da7

Correctly handle null value deserialization in non-generic Deserialize(string, Type) method.
Add files that were forgotten in 6af798962810054fcf68f8e597de56b6490271a2, which is the re-apply of 950d9c8a567273c3363f43cee454f2b95a9f5da7
[llvm] Remove the unused LLVM_MAJOR_VERSION/LLVM_MINOR_VERSION defines.
Add the -Qunused-arguments warning to CPPFLAGS too.
Fix a warning.
[aot] Use the info->tramp_page_code_offsets array on arm as well.
[aot] Remove some obsolete TODOs.
Merge pull request #1381 from schani/fix-23401

Fix 23401
[runtime] Fix the android build with ndk r10c.
[sgen] Add an explanatory comment about OOM.
Merge pull request #1360 from madewokherd/winuncpath

File URI's without a host are not UNC paths on Windows.