RFR: 8293991: java/lang/Float/Binary16ConversionNaN.java fails on silent NaN conversions

[Aleksey Shipilev]

Reliably reproduces on x86-32 with FPU:


$ CONF=linux-x86-server-fastdebug make test TEST=java/lang/Float/Binary16ConversionNaN.java TEST_VM_OPTS="-XX:UseAVX=0 -XX:UseSSE=0"
...
Roundtrip failure on NaN value 7de2 got back 7fe2
Roundtrip failure on NaN value fde2 got back ffe2


Since there are many NaN values in FP16 -- basically any non-zero significand works, we should probably just relax the test a bit.

Attn @jddarcy ;)

Additional testing:
 - [x] Linux x86_32 fastdebug, `-XX:UseAVX=0 -XX:UseSSE=0`, affected test now passes
 - [x]  Linux x86_64 fastdebug, affected test still passes

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

Commit messages:
 - Indenting
 - Fix

Changes: https://git.openjdk.org/jdk/pull/10333/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10333&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293991
  Stats: 44 lines in 1 file changed: 29 ins; 9 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/10333.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10333/head:pull/10333

PR: https://git.openjdk.org/jdk/pull/10333