[jdk13u-dev] RFR: 8253409: Double-rounding possibility in float fma

[Ekaterina Vergizova]

I'd like to backport JDK-8253409 to 13u for parity with 11u.
The patch applies cleanly.
Tested with tier1; new test fails without the patch, passes with it.

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Commit messages:
 - Backport e5304b3a994b1e291e4ac5258f473dd7874f163f

Changes: https://git.openjdk.java.net/jdk13u-dev/pull/154/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk13u-dev&pr=154&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253409
  Stats: 32 lines in 2 files changed: 4 ins; 11 del; 17 mod
  Patch: https://git.openjdk.java.net/jdk13u-dev/pull/154.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk13u-dev pull/154/head:pull/154

PR: https://git.openjdk.java.net/jdk13u-dev/pull/154