MB-40160: Fix expectation on mapped-mem in DefragmenterTest

By comment we expect mapped-mem at some step to be 70% of mapped-mem
from some previous step. But in the actual check we enforce 80%, and
then sometimes the test fails there by tiny error.

I fix by enforcing the 70% as per comment.

Change-Id: I400eb80b4bc5e974e8c07089e2ba294ee261672a
Reviewed-on: http://review.couchbase.org/c/kv_engine/+/155938
Reviewed-by: Dave Rigby <[email protected]>
Tested-by: Paolo Cocchi <[email protected]>

Author: paolococchi

engines/ep/tests/module_tests/defragmenter_test.cc

@@ -239,9 +239,9 @@ TEST_P(DefragmenterTest, DISABLED_MappedMemory) {
     const size_t current_mapped = mapped_2 - mapped_0;
     const size_t previous_mapped = mapped_1 - mapped_0;
 
-    EXPECT_GE(current_mapped, size_t(0.80 * double(previous_mapped)))
+    EXPECT_GE(current_mapped, size_t(0.70 * double(previous_mapped)))
             << "current_mapped memory (which is " << current_mapped
-            << ") is lower than 80% of previous mapped (which is "
+            << ") is lower than 70% of previous mapped (which is "
             << previous_mapped << "). ";
 
     // 3. Enable defragmenter and trigger defragmentation