RFR: 8295302: Do not use ArrayList when LambdaForm has a single ClassData [v3]

[Ioi Lam]

> Please review this small optimization. As shown in the JBS issue, most of the generated LambdaForm classes have a single ClassData, so we can get a small footprint/speed improvement.

Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - Merge branch 'master' into 8295302-no-arraylist-for-single-classdata-for-lambdaform
 - @mlchung comments
 - @iwanowww comments
 - 8295302: Do not use ArrayList when LambdaForm has a single ClassData

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10706/files
  - new: https://git.openjdk.org/jdk/pull/10706/files/5a800f0d..eb05b9ef

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10706&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10706&range=01-02

  Stats: 4613 lines in 133 files changed: 2969 ins; 1034 del; 610 mod
  Patch: https://git.openjdk.org/jdk/pull/10706.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10706/head:pull/10706

PR: https://git.openjdk.org/jdk/pull/10706