[split] Add evm to OWNERS of twitter-server* and util-app

RB_ID=390247
TBR=true
[split] bump util to 6.18.3-SNAPSHOT

RB_ID=412425
TBR=true
[split]  [util-app] fix a bug in global flag parsing

 Problem

 Boolean Flags can be specified on the command line without a value, which is interpreted
 as setting the flag to true. Global boolean Flags, however, cannot; doing so produces
 a key-not-found-in-map exception.

 (also: lots of deprecation warnings in compilation of FlagTest)

 Solution

 The problem was that when parsing Flags with no arguments, the underlying flag Map
 was being accessed directly, rather than going through the flag method, which pulls
 global flags in as well. The case was guarded by a previous case that checked for the
 Flag's existence using the hasFlag method, which also checks both local and global
 Flags. The fix is a one-character change, to call the "flags" method instead of
 looking the key up in the "flag" Map.

 (also: replace calls in FlagTest to "parse" with "parseArgs", reword tests as appropriate)

 Result

 The expected behavior, that global and local boolean Flags can both be
 specified on the command line without a value, is produced.

 (also: no more deprecation warnings for FlagTest)

RB_ID=412557
[split] Remove confusing NOOP 0.until(5) in Future.collect().

RB_ID=412755
[split] Reader and getContent symmetry

Problem

An HTTP message where `isChunked=true` has its content accessible via
`reader`, otherwise it is accessible via `getContent`. Calling
`reader.read` on an HTTP message where `isChunked=false` will suspend
the computation indefinitely.

Solution

In the dispatcher, construct a `reader` sourced by whatever `getContent`
refers to, consumers then retrieve content via `reader` or `getContent`.

Result

Reader and getContent symmetry.

RB_ID=417479
[split] Fix missing BUILD dependency in util-core

RB_ID=420565
TBR=true
[split] util, finagle: smattering of minor cleanups in util and finagle

RB_ID=421029
[split] bump all the things

RB_ID=422405
TBR=true
[split] csl: Fix up sbt for publishing

RB_ID=422613
TBR=true