RFR: JDK-8263411: Convert jshell tool to use Stream.toList() [v2]

[Ian Graves]

> This converts jshell from using `Stream.collect(Collectiors.toList())` to `Stream.toList()` - an immutable list with better performance characteristics. Local inspection only turned up one place that was mutating a resulting list and that has been refactored. 
> 
> This work is a subtask to: https://bugs.openjdk.java.net/browse/JDK-8260559

Ian Graves has updated the pull request incrementally with one additional commit since the last revision:

  Removing most explicit casts and refactoring a Stream use

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2979/files
  - new: https://git.openjdk.java.net/jdk/pull/2979/files/bf0f3cfb..fd520aa0

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2979&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2979&range=00-01

  Stats: 14 lines in 3 files changed: 0 ins; 4 del; 10 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2979.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2979/head:pull/2979

PR: https://git.openjdk.java.net/jdk/pull/2979