rustc: Turn off split stacks on Windows
Disable runtime split stack support on Windows
Add test for #13259. Closes #13259 and #14742
Remove windows TCB hack from rustdoc
Ignore win-tcb test on non-windows
auto merge of #17563 : brson/rust/wintcbfix, r=thestinger

This is the bare minimum to stop using split stacks on Windows, fixing https://github.com/rust-lang/rust/issues/13259 and #14742, by turning on stack probes for all functions and disabling compiler and runtime support for split stacks on Windows.

It does not restore the out-of-stack error message, which requires more runtime work.

This includes a test that the Windows TCB is no longer being clobbered, but the out-of-stack test itself is pretty weak, only testing that the program exits abnormally, not that it isn't writing to bogus memory, so I haven't truly verified that this is providing the safety we claim.

A more complete solution is in https://github.com/rust-lang/rust/pull/16388, which has some unresolved issues yet.

cc @Zoxc @klutzy @vadimcn
librustc: Stop looking in metadata in type contents.

4x improvement in pre-trans compile time for rustc.