Only numbers from the same modular fields can be involved in arithmetic calculations. Add `assert` to guarantee this.
Also, found one broken case and rewrote it. ------------- Commit messages: - ECC calculation error fix Changes: https://git.openjdk.java.net/jdk/pull/8409/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8409&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8285493 Stats: 16 lines in 2 files changed: 3 ins; 4 del; 9 mod Patch: https://git.openjdk.java.net/jdk/pull/8409.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/8409/head:pull/8409 PR: https://git.openjdk.java.net/jdk/pull/8409
