RFR: 8378715: Use early field initialization for java.lang.invoke generated code

[Chen Liang]

With Flexible Constructor Bodies, the preferred way to assign fields for objects is to assign before making a super call. These are all sites in the JDK code that can migrate to the new preferred pattern. This change also allows these fields to be later declared ACC_STRICT_INIT when strict fields JEP is integrated.

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Commit messages:
 - 8378715: Use early field initialization for java.lang.invoke generated code

Changes: https://git.openjdk.org/jdk/pull/29926/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29926&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8378715
  Stats: 29 lines in 3 files changed: 10 ins; 12 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/29926.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29926/head:pull/29926

PR: https://git.openjdk.org/jdk/pull/29926