The two failures may be unrelated, but they may be due to recent changes:
IMPALA-3201: in-memory buffer pool implementation, https://github.com/apache/incubator-impala/commit/241c7e01978f180012453b0a4ff6d061ca6d5093
The previous run of the same job, http://sandbox.jenkins.sf.cloudera.com/view/Impala/view/Evergreen-asf-master/job/impala-asf-master-exhaustive-release/83/#showFailuresLink, also has the same failures. This tests revision 2a31fbdbfac9a7092c96e4ab9894e0db0e4ce9ca which includes
IMPALA-3201: in-memory buffer pool implementation
but not the later one,
IMPALA-4118: extract encryption utils from BufferedBlockMgr
Revision tested in test run #84 was 757c68b29e21e64fc4586cdf24ee6f9369be460f, which includes the above change and https://github.com/apache/incubator-impala/commit/757c68b29e21e64fc4586cdf24ee6f9369be460f
The debug exhaustive build, http://sandbox.jenkins.sf.cloudera.com/view/Impala/view/Evergreen-asf-master/job/impala-asf-master-exhaustive/82/, worked and included the first change, so possibly this only fails with a release build.