[csmith-project/csmith] e16753: Remove the least useful code

[Xuejun Yang <noreply@github.com>]

  Branch: refs/heads/cleanup
  Home:   https://github.com/csmith-project/csmith
  Commit: e167530e0e25a227f6640e4643cf942e76bd9e96
      https://github.com/csmith-project/csmith/commit/e167530e0e25a227f6640e4643cf942e76bd9e96
  Author: jxyang <nitsnow@gmail.com>
  Date:   2019-03-31 (Sun, 31 Mar 2019)

  Changed paths:
    M src/AbsRndNumGenerator.cpp
    M src/AbsRndNumGenerator.h
    M src/ArrayVariable.cpp
    M src/CGOptions.cpp
    M src/CGOptions.h
    M src/CMakeLists.txt
    M src/DefaultOutputMgr.cpp
    M src/DefaultProgramGenerator.cpp
    M src/DefaultRndNumGenerator.cpp
    R src/DeltaMonitor.cpp
    R src/DeltaMonitor.h
    M src/ExpressionAssign.cpp
    M src/ExpressionComma.cpp
    M src/ExpressionFuncall.cpp
    M src/ExpressionVariable.cpp
    M src/ExtensionMgr.cpp
    R src/MspFilters.cpp
    R src/MspFilters.h
    M src/Probabilities.cpp
    M src/RandomProgramGenerator.cpp
    R src/Reducer.cpp
    R src/Reducer.h
    R src/ReducerOutputMgr.cpp
    R src/ReducerOutputMgr.h
    M src/SafeOpFlags.cpp
    M src/SequenceFactory.cpp
    R src/SimpleDeltaRndNumGenerator.cpp
    R src/SimpleDeltaRndNumGenerator.h
    R src/SimpleDeltaSequence.cpp
    R src/SimpleDeltaSequence.h
    R src/SplatExtension.cpp
    R src/SplatExtension.h
    M src/Variable.cpp

  Log Message:
  -----------
  Remove the least useful code

Eager reducer and simple delta reducer: we have proven them to be less
efficient than CReduce.
Msp filters: I suggest we use a new mechanism for silicon vendors to
restrict which arithmetic operations are supported on their processors.
The mechanism should be through a config file, instead of we creating
vendor specific filters in Csmith.
Splat extension: Splat seems to be less popular than klee and crest
nowadays. Even for klee and crest, we should move them out of Csmith in
the future when we have a generic way to support outputing the random
programs in customized ways.