libsnapshot: Disable legacy merge tests.

These are failing on 6.1 kernels. Disabling them since legacy merges +
6.1 is not a supported combination.

Bug: 279009697
Test: vabc_legacy_tests on 6.1 CF
Change-Id: Iddc86f858e1a0101a7823b79fd0e81e221797f33
1 file changed