fix tests & add expected results

Author: jepler

tests/circuitpython/synthio_block_biquad.py

@@ -1,5 +1,5 @@
 from synthnotehelper import *
-from synthio import BlockBiquad, FilterType
+from synthio import BlockBiquad, FilterMode
 import random
 
 random.seed(41)
@@ -10,7 +10,7 @@
 def gen(synth):
     l = LFO(sweep, offset=1440, scale=2880, rate=.025, once=True)
     yield [l]
-    b = BlockBiquad(FilterType.LOW_PASS, l)
+    b = BlockBiquad(FilterMode.LOW_PASS, l)
     n = Note(100, filter=b, waveform=white_noise)
     synth.press(n)
     yield 20