std: Stabilize APIs for the 1.8 release

[alexcrichton]

This commit is the result of the FCPs ending for the 1.8 release cycle for both
the libs and the lang suteams. The full list of changes are:

Stabilized

• braced_empty_structs
• augmented_assignments
• str::encode_utf16 - renamed from utf16_units
• str::EncodeUtf16 - renamed from Utf16Units
• Ref::map
• RefMut::map
• ptr::drop_in_place
• time::Instant
• time::SystemTime
• {Instant,SystemTime}::now
• {Instant,SystemTime}::duration_since - renamed from duration_from_earlier
• {Instant,SystemTime}::elapsed
• Various Add/Sub impls for Time and SystemTime
• SystemTimeError
• SystemTimeError::duration
• Various impls for SystemTimeError
• UNIX_EPOCH
• ops::{Add,Sub,Mul,Div,Rem,BitAnd,BitOr,BitXor,Shl,Shr}Assign

Deprecated

• Scoped TLS (the scoped_thread_local! macro)
• Ref::filter_map
• RefMut::filter_map
• RwLockReadGuard::map
• RwLockWriteGuard::map
• Condvar::wait_timeout_with

Closes #27714
Closes #27715
Closes #27746
Closes #27748
Closes #27908
Closes #29866
Closes #28235
Closes #29720

[rust-highfive]

r? @aturon

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[aturon]

Argh, this is another one of those cases where we don't really want the deprecation to go into effect on nightly until 1.8 is actually on the stable channel. This is probably used rarely enough that it doesn't matter, but we really need to get our story straight there.

[alexcrichton]

Isn't that just for deprecating stable APIs? For deprecating unstable APIs everyone should be able to immediately switch, right?

[aturon]

Gah, I make this mistake every time. Ignore me.

[aturon]

Yay, some very good stuff in this one! I left a few concerns here and there.

[alexcrichton]

@bors: r=aturon ffef000f46147084000f7fd125335aaa043cedf3

[Manishearth]

../src/libstd\sys/windows\compat.rs:31:39: 31:50 error: use of deprecated item: renamed to encode_utf16, #[deny(deprecated)] on by default
../src/libstd\sys/windows\compat.rs:31     let mut module: Vec<u16> = module.utf16_units().collect();
                                                                             ^~~~~~~~~~~
../src/libstd\sys/windows\stdio.rs:59:28: 59:39 error: use of deprecated item: renamed to encode_utf16, #[deny(deprecated)] on by default
../src/libstd\sys/windows\stdio.rs:59         Some(utf8) => utf8.utf16_units().collect::<Vec<u16>>(),
                                                                 ^~~~~~~~~~~
error: aborting due to 2 previous errors

[bors]

⌛ Testing commit ffef000 with merge 18a736a...

[bors]

💔 Test failed - auto-win-msvc-32-opt

[alexcrichton]

@bors: r=aturon aa7c581

[bors]

⌛ Testing commit aa7c581 with merge c7a3250...

[bors]

💔 Test failed - auto-win-msvc-64-opt

[Manishearth]

../src/libstd\sys/windows\stdio.rs:59:28: 59:39 error: use of deprecated item: renamed to encode_utf16, #[deny(deprecated)] on by default
../src/libstd\sys/windows\stdio.rs:59         Some(utf8) => utf8.utf16_units().collect::<Vec<u16>>(),
                                                                 ^~~~~~~~~~~

[alexcrichton]

@bors: r=aturon 7dc363c

[bors]

⌛ Testing commit 7dc363c with merge 1573036...

[bors]

💔 Test failed - auto-linux-64-nopt-t

[alexcrichton]

@bors: r=aturon 95560c1

cc @brson, @nrc

The most recent failure log matches the failures seen on #31335. These valgrind failures are unfortunately preventing things from landing, so we need a fix fr them soon. In 595d5b2 I fixed a test by adding // no-prefer-dynamic (compile tests statically instead of dynamically) and that seemed to at least paper over the bug.

I'm not really sure what's going on here with valgrind, but as part of this PR (to land it) I'm updating all tests to have that flag. This is gonna close #30383 but I'll open a new issue about tracking this.

[bors]

⌛ Testing commit 95560c1 with merge 52cb8a9...

[alexcrichton]

Tracking issue: #31968

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-mac-ios-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-opt