[code-reflection] RFR: Remove MethodTypeDesc [v2]

[Paul Sandoz]

> Remove `MethodTypeDesc` and replace with usages of `FunctionType`, with functionality to convert between nominal description `java.lang.constant.MethodTypeDesc` (from which it can be resolved to `java.lang.invoke.MethodType`).

Paul Sandoz has updated the pull request incrementally with one additional commit since the last revision:

  Rename

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Changes:
  - all: https://git.openjdk.org/babylon/pull/31/files
  - new: https://git.openjdk.org/babylon/pull/31/files/06d24936..e302e83c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=31&range=01
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=31&range=00-01

  Stats: 7 lines in 3 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/babylon/pull/31.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/31/head:pull/31

PR: https://git.openjdk.org/babylon/pull/31