Windows dbghelp strips leading underscores from symbols, so let's accept "ZN...E" form too.
Also, print PC displacement from symbols.
Fix typo
Add tests for E-needstest issues
Propagate coercions through match expressions.
auto merge of #19769 : nick29581/rust/coerce-if, r=nikomatsakis

r? @nikomatsakis 

We discussed coercions for `if` and `match` expressions. `if` seems to work already, was there some specific behaviour which wasn't working?
auto merge of #19780 : jakub-/rust/e-needstest, r=alexcrichton

Closes #5988.
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auto merge of #19819 : vadimcn/rust/fix-demangle, r=alexcrichton

Windows dbghelp strips leading underscores from symbols, and I could not find a way to turn this off.  So let's accept  "ZN...E" form too.
Also, print PC displacement from symbols.  This is helpful in gauging whether the PC was indeed within the function displayed in the backtrace, or whether it just happened to be the closest public symbol in the module.
Register new snapshots

This does not yet start the movement to rustc-serialize. That detail is left to
a future PR.