Remove bad chain alert partition check

As per meeting 2016-03-31
https://bitcoincore.org/en/meetings/2016/03/31/#bad-chain-alerts

The partition checker was producing huge number of false-positives
and was disabled in 0.12.1 on the understanding it would either be
fixed in 0.13 or removed entirely from master if not.

src/Makefile.test.include

@@ -38,7 +38,6 @@ BITCOIN_TESTS =\
   test/arith_uint256_tests.cpp \
   test/scriptnum10.h \
   test/addrman_tests.cpp \
-  test/alert_tests.cpp \
   test/amount_tests.cpp \
   test/allocator_tests.cpp \
   test/base32_tests.cpp \