[PATCH v2 1/5] add isfinite builtin

v2: simplify and remove isinf leftovers
    remove trailing newline

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

v2: simplify and remove isnan leftovers
    remove trailing newline

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

v2: remove trailing newline

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

v2: remove trailing newline

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>