The msc_vlr_tests verify whether any of the tests run contain msgb or
talloc memory leaks. So far they did so by fixating a specific number of
talloc blocks, which may break by library implementations changing.
Instead, verify that the test leaks no allocations by comparing talloc
blocks before and after each test.
When a leak is detected, print the full talloc report to stderr, which
makes the expected output mismatch the actual output and fails the test.
Related: OS#4311
Change-Id: I8537fa76d460c951302932a1bad4299f7fe398c9
dbb3c723a4