Update cmake to use a custom target TestBinaries instead of a list of targets.
This simplifies cmake, and fix some errors. This way, we don't have to propagate
the values into parents directories. We only need to use add_dependencies.

Differential Revision: https://reviews.llvm.org/D29593

llvm-svn: 294389

Add a new CMake function (``add_libfuzzer_test()``) to simplify
declaration of executables for testing LibFuzzer and use it to
reorganise how tests are declared.

Note that configuration of the lit configuration files has been moved
as late as possible because we are going to need to disable some tests
for some platforms and we will need to propagate this information into
the lit configuration.

Note the code for custom mains was removed because no tests are
currently written for this and Kostya seems happy to remove this.

Differential Revision: http://reviews.llvm.org/D20706

llvm-svn: 270958

Previously the flags were only being set correctly when the
build type was "Release". Now the build should work properly
for all the supported build types. When building libFuzzer
the optimization level respects whatever is used for the
rest of LLVM but for the LibFuzzer tests we force -O0.

Differential Revision: http://reviews.llvm.org/D20558

llvm-svn: 270912

llvm-svn: 268968