tests: Use float constants and parameters when testing float opcodes.

5 jobs for fix_test_exec_float in 2 minutes and 7 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #502247
debian sid

00:00:45

passed #502250
docker windows 1607
msys2

00:01:02

passed #502248
docker windows 1607
vs2017 amd64

00:01:09

passed #502251
docker windows 1607
vs2017 x86

00:00:57

failed #502249
docker windows 1607
vs2017 x86

00:00:00