Generalize parsing of externalized type forms

[mcimadamore]

This draft PR contains some preliminary work to generalize parsing of externalized type forms, as well as to making Java type string in code models more readable.

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Progress

• [x] Change must not contain extraneous whitespace

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/babylon.git pull/428/head:pull/428
$ git checkout pull/428

Update a local copy of the PR:
$ git checkout pull/428
$ git pull https://git.openjdk.org/babylon.git pull/428/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 428

View PR using the GUI difftool:
$ git pr show -t 428

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/babylon/pull/428.diff

[bridgekeeper[bot]]

:wave: Welcome back mcimadamore! A progress list of the required criteria for merging this PR into code-reflection will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk[bot]]

❗ This change is not yet ready to be integrated. See the Progress checklist in the description for automated requirements.

[openjdk[bot]]

@mcimadamore this pull request can not be integrated into code-reflection due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout generalized_extype_parser
git fetch https://git.openjdk.org/babylon.git code-reflection
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge code-reflection"
git push