[code-reflection] RFR: Update ReflectMethods.BodyScanner.coerce to handle null targetType [v3]

[Mourad Abbay]

> `ReflectMethods.BodyScanner.coerce` wasn't handling `null` targetType. For example, a `null` targetType may propagate to reach the method `coerce` when visiting case body of switch statement.

Mourad Abbay has updated the pull request incrementally with one additional commit since the last revision:

  Apply suggestions

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Changes:
  - all: https://git.openjdk.org/babylon/pull/536/files
  - new: https://git.openjdk.org/babylon/pull/536/files/3b7ad47a..46768674

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=babylon&pr=536&range=02
 - incr: https://webrevs.openjdk.org/?repo=babylon&pr=536&range=01-02

  Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/babylon/pull/536.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/536/head:pull/536

PR: https://git.openjdk.org/babylon/pull/536