RFR: SKARA-1194: Implement git webrev --no-comments option [v2]

[Aleksey Shipilev]

> hg webrev had a `-C` / `--no-comments` option that skipped printing the comments for each file, i.e. commit messages. GitWebrev accepts the same option, but it does not seem to be implemented. Producing a webrev for a branch with a lot of commits looks badly then.
> 
> For example, current report with `-C`:
> 
> 
>  ------ ------ ------ ------ --- New Patch Raw doc/panama_jextract.html
> 
>     8065b5cc: 8270898: update panama_jextract.md and panama_jextract.html files
>     bedc58a3: 8257892: long double not handled by jextract
>     2d966367: Consolidate all the various documents in the repository.
>     3dc23ea0: 8253419: jextract should generate RuntimeHelper as a package private class
>     52adf7f5: updating samples for CSupport->CLinker
>     33cba7a0: adding tensorflow sample
>     06675b1e: updating samples. changed constants class to use package constructor
>     6809ef51: Samples update after 8249879. Added opengl sample
>     abb6e377: updating samples for recent MemoryAccess changes.
>     ebba5406: 8248710: jextract should not generate Cstring, Cpointer, Cint C-X utility classes
>     45d41d75: * Fixed include path to be OS/SDK version independent
>     ...
> 
>     992 lines changed; 992 ins; 0 del; 0 mod; 0 unchg
> 
> 
> Fixed report with `-C`:
> 
> 
>  ------ ------ ------ ------ --- New Patch Raw doc/panama_jextract.html
> 
>     992 lines changed; 992 ins; 0 del; 0 mod; 0 unchg 
> 
> 
> Additional testing:
>  - [x] Eyeballing the reports with/without `-C`

Aleksey Shipilev 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 three additional commits since the last revision:

 - Merge branch 'master' into SKARA-1194-git-webrev-no-comments
 - Avoid negation in field names
 - Fix

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

Changes:
  - all: https://git.openjdk.java.net/skara/pull/1224/files
  - new: https://git.openjdk.java.net/skara/pull/1224/files/88ccff0a..c5ea0f23

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=1224&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=1224&range=00-01

  Stats: 84 lines in 8 files changed: 59 ins; 7 del; 18 mod
  Patch: https://git.openjdk.java.net/skara/pull/1224.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1224/head:pull/1224

PR: https://git.openjdk.java.net/skara/pull/1224