RFR: 8374643: Fix reference to implMethodKind in LambdaToMethod debug printf statement [v2]

[Liam Miller-Cushon]

> This change extracts a local variable, to allow the commented-out printf debug statement below to work without additional modifications.
> 
> 
> System.err.printf("*implMethodKind: %d\n", implMethodKind);

Liam Miller-Cushon has updated the pull request incrementally with one additional commit since the last revision:

  Add an -XD flag for lambda deserialization diagnostic output

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29072/files
  - new: https://git.openjdk.org/jdk/pull/29072/files/21060f13..67f1f7e4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29072&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29072&range=00-01

  Stats: 30 lines in 4 files changed: 19 ins; 0 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/29072.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29072/head:pull/29072

PR: https://git.openjdk.org/jdk/pull/29072