RFR: 7903146: TypeTranslator is no longer needed

[Maurizio Cimadamore]

Now that ValueLayout has carrier information attached, we no longer need to perform two separate visit on a function type, one to get a FunctionDescriptor and one to get a MethodType. We can just get a FunctionDescriptor and derive everything from there.

This patch applies several cleanups on OutputFactory, to flatten the code, and remove some spaghetti lambdas. It also drops the FunctionInfo/VarInfo abstraction, since now that we can derive most of the info from layouts, these do not seem to add much value.

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Commit messages:
 - Drop VarInfo
 - Drop FunctionINfo
 - Initial push
 - Merge branch 'cleanup_treemaker' into drop_type_translator
 - Address review comments
 - Drop TypeTranslator
 - Merge branch 'master' into cleanup_treemaker
 - Initial push

Changes: https://git.openjdk.java.net/jextract/pull/14/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jextract&pr=14&range=00
  Issue: https://bugs.openjdk.java.net/browse/CODETOOLS-7903146
  Stats: 478 lines in 11 files changed: 85 ins; 249 del; 144 mod
  Patch: https://git.openjdk.java.net/jextract/pull/14.diff
  Fetch: git fetch https://git.openjdk.java.net/jextract pull/14/head:pull/14

PR: https://git.openjdk.java.net/jextract/pull/14