RFR: 8271225: Add floorDivExact() method to java.lang.[Strict]Math [v2]

[Brian Burkhalter]

> Add methods `floorDivExact(int,int)` and `floorDivExact(long,long)` to `java.lang.Math` and `java.lang.StrictMath`.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8271225: Some verbiage updates

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4941/files
  - new: https://git.openjdk.java.net/jdk/pull/4941/files/03e83cda..7601fe9b

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4941&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4941&range=00-01

  Stats: 20 lines in 2 files changed: 0 ins; 0 del; 20 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4941.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4941/head:pull/4941

PR: https://git.openjdk.java.net/jdk/pull/4941