Tests: Fix bug with throttle rate in specs
Tests: Fix bug with throttle rate in specs

These tests were erroneously being run without a throttle rate.  Since we need
all updates to the bar during a test run, the throttle rate should always be
`0.0`.

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Signed-off-by: Jeff Felchner <8a84c204e2d4c387d61d20f7892a2bbbf0bc8ae8@thekompanee.com>

jfelchner/ruby-progressbar,jfelchner/ruby-progressbar