After changes to the bug fix for bug 26379 (Combination of FLUSH
TABLE and REPAIR TABLE corrupts a MERGE table) the test case
merge-big failed.
Repaired the test case.
Removed tests for INSERT ... SELECT, which is disabled for MERGE.
Test case change only.


mysql-test/r/merge-big.result:
  Bug#34376 - merge-big test fails
  Removed result for removed tests.
mysql-test/t/merge-big.test:
  Bug#34376 - merge-big test fails
  Repaired the test case.
  Removed tests for INSERT ... SELECT, which is disabled for MERGE.