fix builtin function 'frexp'
fix builtin function 'frexp'

returns correct value for nan or inf.
also returns correct value for very small float value.

Signed-off-by: Homer Hsing <f17cb7083eb6a94c3fb9d8f09ceefa518f721ab2@intel.com>
Reviewed-by: "Yang, Rong R" <78759e37dc7114caed18f74e7515c5cb519dbf6d@intel.com>

freedesktop-unofficial-mirror/beignet,wdv4758h/beignet,freedesktop-unofficial-mirror/beignet,zhenyw/beignet,zhenyw/beignet,wdv4758h/beignet,zhenyw/beignet,ignatenkobrain/beignet,zhenyw/beignet,wdv4758h/beignet,ignatenkobrain/beignet,zhenyw/beignet,ignatenkobrain/beignet,freedesktop-unofficial-mirror/beignet,freedesktop-unofficial-mirror/beignet,wdv4758h/beignet,ignatenkobrain/beignet,ignatenkobrain/beignet,wdv4758h/beignet