Fix frexp packetmath tests for MSVC.
Silly MSVC, frexp sets the exponent to 1 for non-finite inputs when the docs say the output
is "unspecified". Our tests assume it remains zero, so we need to reset it for our reference value.
Silly MSVC, frexp sets the exponent to 1 for non-finite inputs when the docs say the output
is "unspecified". Our tests assume it remains zero, so we need to reset it for our reference value.