[evlatests] Updated levels for ea18 and ea24

[Walter Brisken]

I put in new values for:

ea18 : K, Q bands, all IFs
ea24 : X band, IFs A/C  (low but not extremely low power from receiver)

I wasn't able to derive atten settings for:

ea18 C-band -- no power
ea24 L-band -- no power



-Walter