ICat silently fails to interpolate through gaps in Phoenix catalog

[pllim]

Example gap, as seen in header of phoenixm05/phoenixm05_2000.fits:

TEFF    = '2000    '           / Effective Temperature in K                     
LOG_Z   = '-0.5    '           / Log value of stellar  metallicity              
FLUXUNT = 'Flambda '           /  erg/cm^2/s/Angstrom                           
LOGG1   = '-999    '                                                            
LOGG2   = '-999    '                                                            
LOGG3   = '-999    '                                                            
LOGG4   = '-999    '                                                            
LOGG5   = '-999    '                                                            
LOGG6   = '-999    '                                                            
LOGG7   = '-999    '                                                            
LOGG8   = '-999    '                                                            
LOGG9   = '4.0     '                                                            
LOGG10  = '4.5     '                                                            
LOGG11  = '-999    '                                                            
LOGG12  = '-999    '           

Solution, until data are fixed, is to raise exception when interpolation detects a gap within the rectangular boundaries. Can possibly even reuse ParameterOutOfBounds exception.
Full bug report https://jira.stsci.edu/browse/REDCAT-48

c/c @mgennaro @vglaidler

[pllim]

Recently a regression test that would catch this ParameterOutOfBounds for gaps no longer fails. I think the gaps have been fixed in TRDS. If that is not the case, please let me know.