ITS: test_tonemap_curve.py widen stripped area around color boundaries

DELTA (keep out width on each side of color bar) width was 0.0005.
This created 0.1% shrink of color bar. Target was actually 1%.

bug: 233702673

Other changes:
  spelling correction
  pylint spacings
  remove redundant logging

Change-Id: I6fb0a3cea3a40bd237d9231f787d98d22b924842
1 file changed