Make `DirectCodeBuilder` write instructions actually directly without allocating extra objects. This speed up a lot of simple Class-File building cases that never go through intermediate transforms.
------------- Commit messages: - Moar fixes - More direct code builder Changes: https://git.openjdk.org/jdk/pull/20738/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20738&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8339132 Stats: 772 lines in 4 files changed: 719 ins; 25 del; 28 mod Patch: https://git.openjdk.org/jdk/pull/20738.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/20738/head:pull/20738 PR: https://git.openjdk.org/jdk/pull/20738
