[BE] Fix BIN rendering with 20ms path when split rend switch is off

Basic Info

• Related issues: #756 (closed)
• Requested reviewers: @kiene, @pihlajakuja @tamarapu

Reason why this change is needed

• Fix BIN rendering with 20ms path when split rend switch is off

Description of the change

• Updates the renderer to use number of subframes when calculating the number of output samples.
• Removes some expected fails for binaural rendering pytests.

Affected operating points

• BE but add more tests due to the removal of expected fails.