Recanonicalise test/test.pl whitespace -- USE -b/-w TO DIFF/BLAME

This file had a mixture of 4-space and 8-space tabs, which previously
went unnoticed.  Manually re-expand tabs to spaces using the right
number of spaces for each tab.

See notes in fcb8af08a6fd3bfcf195407c4ba5bae528ee326d.