Simple refactoring of merging two types. Test: tier1-5
------------- Commit messages: - merge-type Changes: https://git.openjdk.org/jdk/pull/12841/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12841&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8303534 Stats: 191 lines in 14 files changed: 27 ins; 122 del; 42 mod Patch: https://git.openjdk.org/jdk/pull/12841.diff Fetch: git fetch https://git.openjdk.org/jdk pull/12841/head:pull/12841 PR: https://git.openjdk.org/jdk/pull/12841
