RFR: 8257912: Convert enum iteration to use range-based for loops [v2]

[Ioi Lam]

> Now that [range-based for loops](https://github.com/openjdk/jdk/pull/1488) are allowed by the [HotSpot Style Guide](https://github.com/openjdk/jdk/blob/52ab72127ddc3ca6575d9d58503ec39c5dff7ab1/doc/hotspot-style.md), I have converted the more verbose syntax:
> 
> for (vmIntrinsicsIterator it = vmIntrinsicsRange.begin(); it != vmIntrinsicsRange.end(); ++it) {
>   vmIntrinsicID index = *it;
>   nt[as_int(index)] = string;
> }
> 
> to
> 
>   for (vmIntrinsicID index : EnumRange<vmIntrinsicID>{}) {
>     nt[as_int(index)] = string;
>   }
> 
> I also removed the "convenient" declarations such as `vmIntrinsicsRange` and `vmIntrinsicsIterator` -- these are useful only when writing a traditional for loop, and are probably confusing to everyone else.  I've left examples in enumIterator.hpp in case anyone wants to write a traditional for loop.
> 
> I also added gtest cases for using range-based for loops with `EnumRange<>`.

Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:

 - Merge branch 'master' into 8257912-range-based-for-loop
 - 8257912: Convert enum iteration to use range-based for loops

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1707/files
  - new: https://git.openjdk.java.net/jdk/pull/1707/files/26ad3f0d..ceaebeeb

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1707&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1707&range=00-01

  Stats: 15530 lines in 289 files changed: 13089 ins; 1590 del; 851 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1707.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1707/head:pull/1707

PR: https://git.openjdk.java.net/jdk/pull/1707