Fix incorrect number formatting in dumpsys meminfo

This change updates the printRow() helper method that
ActivityThread.dumpMemInfo() references to include Locale.US, so that
numbers will be formatted correctly.

This change also replaces an incorrect %s with %d in the format string
used for three-column rows.

Test: Change the system locale to a different language (Arabic) and
      verify that dumpsys meminfo produces correctly-formatted values.
Bug: 301934161
Change-Id: If814796a1cf0302a54a02fa23e82d21a3213ea10