Clean up TestRunner and fix unit test environment
Clean up TestRunner and fix unit test environment

Commit 7ac0b6 added a ::testing::Environment with the intent of setting
the log levels before each unit test. However, this actually only ran
once at initialization time, not for each test, so unit tests could
still interfere with each other. This commit fixes the problem by
changing to callbacks of a ::testing::TestEventListener, which get run
before and after each individual test.

This commit also cleans up some more dead code in TestRunner.

IMCG/RamCloud,anirajk/RAMCloud,anirajk/RAMCloud,rstutsman/RAMCloud,behnamm/cs244b_project,DavidLi2010/ramcloud,Frank-Wu/RamCloud,behnamm/cs244b_project,anirajk/RAMCloud,SMatsushi/RAMCloud,jblomer/ramcloud,IMCG/RamCloud,DavidLi2010/ramcloud,jcarreira/ramcloud,IMCG/RamCloud,y-higuchi/ramcloud,Frank-Wu/RamCloud,taschik/ramcloud,QingkaiLu/RAMCloud,IMCG/RamCloud,utah-scs/RAMCloud,jblomer/ramcloud,utah-scs/RAMCloud,rstutsman/RAMCloud,jcarreira/ramcloud,taschik/ramcloud,IMCG/RamCloud,QingkaiLu/RAMCloud,jblomer/ramcloud,DavidLi2010/ramcloud,matrix207/RAMCloud,matrix207/RAMCloud,utah-scs/RAMCloud,utah-scs/RAMCloud,jblomer/ramcloud,QingkaiLu/RAMCloud,DavidLi2010/ramcloud,jcarreira/ramcloud,taschik/ramcloud,jcarreira/ramcloud,DavidLi2010/ramcloud,Frank-Wu/RamCloud,matrix207/RAMCloud,matrix207/RAMCloud,y-higuchi/ramcloud,y-higuchi/ramcloud,y-higuchi/ramcloud,alexandermerritt/ramcloud,jcarreira/ramcloud,SMatsushi/RAMCloud,Frank-Wu/RamCloud,taschik/ramcloud,utah-scs/RAMCloud,alexandermerritt/ramcloud,mrdiegoa/ramcloud,taschik/ramcloud-load-manager,jblomer/ramcloud,behnamm/cs244b_project,y-higuchi/ramcloud,alexandermerritt/ramcloud,behnamm/cs244b_project,taschik/ramcloud-load-manager,matrix207/RAMCloud,rstutsman/RAMCloud,alexandermerritt/ramcloud,taschik/ramcloud-load-manager,behnamm/cs244b_project,rstutsman/RAMCloud,mrdiegoa/ramcloud,anirajk/RAMCloud,mrdiegoa/ramcloud,jcarreira/ramcloud,rstutsman/RAMCloud,QingkaiLu/RAMCloud,mrdiegoa/ramcloud,anirajk/RAMCloud,QingkaiLu/RAMCloud,mrdiegoa/ramcloud,matrix207/RAMCloud,SMatsushi/RAMCloud,alexandermerritt/ramcloud,anirajk/RAMCloud,SMatsushi/RAMCloud,Frank-Wu/RamCloud,DavidLi2010/ramcloud,y-higuchi/ramcloud,QingkaiLu/RAMCloud,SMatsushi/RAMCloud,SMatsushi/RAMCloud,jblomer/ramcloud,taschik/ramcloud-load-manager,IMCG/RamCloud,alexandermerritt/ramcloud,taschik/ramcloud,utah-scs/RAMCloud,Frank-Wu/RamCloud,mrdiegoa/ramcloud,rstutsman/RAMCloud,taschik/ramcloud-load-manager,behnamm/cs244b_project