Description:
------------
Recently, WL#2955 introduced a new test suite 'rpl_many_mysqlds' which
contains tests that should not be parallelized by MTR because they
require many mysqlds. Due to this, a lot of new MTR runs are added in
collection files to run these tests with parallel value 1.

Fix:
----
- Enhance MTR to filter out the tests sourcing 'not_parallel.inc'
  file. Tests sourcing not_parallel.inc are marked as 'non-parallel'
  tests. These tests are run at the end with parallel value of 1
  overriding the '--parallel' option value.

  Note: Running non-parallel tests also needs 'run-non-parallel-tests'
        option to be enabled.

- Move all the tests under rpl_many_mysqlds suite to rpl suite and
  modify all the tests to be a big-test.

- Remove the MTR command lines added for rpl_many_mysqlds from
  collection files.

- Modified default.daily, default.release.in, defaule.weekly and
  default.weekly-valgrind collection files to run 'non-parallel'
  tests.

Change-Id: I4e664cb74b801c2989b8add53d4fb792b9beded2