RFR: Use isnan instead of isnanf

[Mikael Vidstedt]

isnanf is not available in musl. posix says that isnan handles both float and double arguments (typically through a macro checking the size of the operand and delegation to the corresponding/actual isnan primitive).

This change makes the two JDK wrapper macros call isnan instead of isnanf. I’ve tried to verify that the toolchains I have access to does the Right(tm) thing for float, but additional verification/testing is probably warranted before this is “productized”.

hotspot: http://cr.openjdk.java.net/~mikael/webrevs/portola/isnan/webrev.00/hotspot/webrev/
jdk: http://cr.openjdk.java.net/~mikael/webrevs/portola/isnan/webrev.00/jdk/webrev/

Cheers,
Mikael