Added failing test for partially filled buffer average

modules/database/test/std/rec/compressTest.db

@@ -1,11 +1,12 @@
 record(ai, "ai") {}
 record(waveform, "wf") {
   field(FTVL, "DOUBLE")
-  field(NELM, "4")
+  field(NELM, "$(N=1)")
 }
 record(compress, "comp") {
   field(INP, "$(INP) NPP")
   field(ALG, "$(ALG)")
+  field(PBUF,"$(PARTIAL=NO)")
   field(BALG,"$(BALG)")
   field(NSAM,"$(NSAM)")
   field(N,   "$(N=1)")