Telemetry: Don't use scientific notation for floats when printing results.

When parsing results for the dashboard we don't expect any letters (such as the
'e' in scientific notation) in the string of values. This CL makes sure we don't
use scientific notation for printing floats.

BUG=318093

Review URL: https://codereview.chromium.org/71543002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234829 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234829