RFR: JDK-8303798: REDO - Remove fdlibm C sources

[Joe Darcy]

This PR is a redo of JDK-8302801: Remove fdlibm C sources. The problem with JDK-8302801 was that it neglected (mea culpa) to include a Java implementation of IEEEremainder before the FDLIBM C implementation was deleted. Such an implementation has been successfully provided under JDK-8304028: Port fdlibm IEEEremainder to Java. After JDK-8304028, there are no native methods left in StrictMath.

This PR is the same as JDK-8302801 other than StrictMath.c already being removed under JDK-8304028.

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

Commit messages:
 - JDK-8303798: REDO - Remove fdlibm C sources

Changes: https://git.openjdk.org/jdk/pull/13279/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13279&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8303798
  Stats: 6516 lines in 64 files changed: 20 ins; 6486 del; 10 mod
  Patch: https://git.openjdk.org/jdk/pull/13279.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13279/head:pull/13279

PR: https://git.openjdk.org/jdk/pull/13279