[llvm-debuginfo-analyzer] (07/09) - Compare elements

The test case 'CompareElements' caused a failure in:

  https://lab.llvm.org/buildbot#builders/5/builds/28502
  https://lab.llvm.org/buildbot#builders/168/builds/9671
  SUMMARY: AddressSanitizer: 2144 byte(s) leaked in 14 allocation(s).

The 'Insert' function conditionally adds the 'Child' logical
element to a logical scope. The not added logical elements,
caused the memory leak. Just record them to be destroyed
when the logical reader is destroyed.

Changed 'EXPECT_NE' with 'ASSERT_NE'.
Missing in the main review.