RFR: 8264610: Number.{byteValue, shortValue} spec should use @implSpec

Please review this small code change and its accompanying CSR: https://bugs.openjdk.java.net/browse/JDK-8264610 ------------- Commit messages: - Update second method. - 8264609: Number.shortValue spec should use @implSpec Changes: https://git.openjdk.java.net/jdk/pull/3314/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3314&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8264610 Stats: 5 lines in 1 file changed: 2 ins; 0 del; 3 mod Patch: https://git.openjdk.java.net/jdk/pull/3314.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/3314/head:pull/3314 PR: https://git.openjdk.java.net/jdk/pull/3314