Tests are failing due to "apitrace --diff" change

After a recent sync to upstream, the following tests were found to be
failing:

   cli/cli-trim-no-side-effects-prune-and-trim.script
   cli/cli-trim-no-side-effects-prune.script
   cli/cli-trim-no-side-effects-trim.script
   cli/cli-trim-spec-all.script
   cli/cli-trim-spec-drawing.script
   cli/cli-trim-spec-shaders.script
   cli/cli-trim-spec-textures.script
   cli/cli-trim-unused-shaders.script
   cli/cli-trim-unused-textures.script

Cause of failure found to be due to commit
155380f 2013-10-18 tracediff: Rename --diff=TOOL option to --tool=TOOL.

Fix was to change scripts to all the failing tests to use "--tool"
instead of "--diff"

TESTING
--------
Re-ran test suite and all tests passed.

Checked "apitrace help diff" output to confirm reflection of "--tool"
change

Looked through markdown documentation. Didn't find any changes that
needed to be made.

Signed-off-by: Lawrence L Love <lawrencex.l.love@intel.com>