[Flang] Revert/Fix some bot changes. (#275)

For the time being, change the Flang bot config to something without
libcxx, libunwind, compiler-rt.
This is an attempt to bring the bot back to green and guarantee some
coverage.

The issues that showed up:
- Enabling libunwind as default unwind library leads to
file-not-found-errors in the OpenMP tests.
- [edit] Adding libunwind also makes Offload believe the system is 32
bit and not build the offload library [/edit]
- Enabling compiler-rt and not libunwind leads to a failing build of
some parts of archer.
- Removing libunwind and compiler-rt while enabling libcxx/libcxx-abi
does lead to a CMake error that it wants to use libunwind, but that is
not specified.

buildbot/osuosl/master/config/builders.py

@@ -1940,8 +1940,8 @@
     'builddir': "openmp-offload-amdgpu-clang-flang",
     'factory' : OpenMPBuilder.getOpenMPCMakeBuildFactory(
                         clean=True,
-                        enable_runtimes=['compiler-rt', 'libunwind', 'libcxx', 'libcxxabi', 'openmp', 'offload'],
-                        depends_on_projects=['llvm','clang','lld', 'offload', 'openmp','flang', 'compiler-rt', 'libcxx', 'libcxxabi', 'libunwind'],
+                        enable_runtimes=['compiler-rt', 'openmp', 'offload'],
+                        depends_on_projects=['llvm','clang','lld', 'offload', 'openmp','flang', 'compiler-rt'],
                         extraCmakeArgs=[
                             "-DCMAKE_BUILD_TYPE=Release",
                             "-DCLANG_DEFAULT_LINKER=lld",
@@ -1950,22 +1950,15 @@
                             "-DCMAKE_C_COMPILER_LAUNCHER=ccache",
                             "-DCMAKE_CXX_COMPILER_LAUNCHER=ccache",
                             "-DFLANG_RUNTIME_F128_MATH_LIB=libquadmath",
-                            "-DLIBCXX_ENABLE_SHARED=OFF",
-                            "-DLIBCXX_ENABLE_STATIC=ON",
-                            "-DLIBCXX_INSTALL_LIBRARY=OFF",
-                            "-DLIBCXX_INSTALL_HEADERS=OFF",
-                            "-DLIBCXXABI_ENABLE_SHARED=OFF",
-                            "-DLIBCXXABI_ENABLE_STATIC=ON",
-                            "-DLIBCXXABI_INSTALL_STATIC_LIBRARY=OFF",
-                            "-DLLVM_ENABLE_ZLIB=ON",
-                            "-DLLVM_ENABLE_Z3_SOLVER=OFF",
                             "-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON",
                             "-DCMAKE_CXX_STANDARD=17",
                             "-DBUILD_SHARED_LIBS=ON",
-                            "-DLLVM_ENABLE_LIBCXX=ON",
-                            "-DCLANG_DEFAULT_RTLIB=compiler-rt",
-                            "-DCLANG_DEFAULT_UNWINDLIB=libunwind",
                             "-DLIBOMPTARGET_PLUGINS_TO_BUILD=amdgpu;host",
+                            "-DCOMPILER_RT_BUILD_ORC=OFF",
+                            "-DCOMPILER_RT_BUILD_XRAY=OFF",
+                            "-DCOMPILER_RT_BUILD_MEMPROF=OFF",
+                            "-DCOMPILER_RT_BUILD_LIBFUZZER=OFF",
+                            "-DCOMPILER_RT_BUILD_SANITIZERS=ON",
                             ],
                         env={
                             'HSA_ENABLE_SDMA':'0',