Mask result with qNaN if input to rint is NaN

This CL masks the output with qNaN for rint of FP16 NaN values
i.e. mask the most significant mantissa bit with 1. In ARM hardware,
the rest of the mantissa bits are still processed when input is NaN,
therefore the mask comes at the end of the rint function.

Test: cts-tradefed  run singleCommand cts-dev --module CtsLibcoreTestCases --test libcore.libcore.util.FP16Test
Change-Id: I431ea90e22b813491d2cdb95daf9b186c7ca15f2
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
2 files changed