libsyntax: Make managed box `@` patterns obsolete
librustc: Remove `@` pointer patterns from the language
auto merge of #11305 : pcwalton/rust/at-patterns, r=pcwalton

r? @nikomatsakis
librustc: Don't allow use after move of implicitly coerced object. Fixes #11481.
librustc: Don't translate an expr twice when implicitly coercing to a trait object. Fixes #11197.
auto merge of #11525 : luqmana/rust/trait-coercions, r=pcwalton

Fixes 2 annoying issues with implicit trait object coercion: #11481 & #11197.
mk: Make TESTNAME and VERBOSE work with android. Closes #10957
std: Ignore bind error tests on android. #11530
auto merge of #11531 : brson/rust/yetmoreandroidfixes, r=alexcrichton
Allow more "error" values in try_recv()

This should allow callers to know whether the channel was empty or disconnected
without having to block.

Closes #11087