Reland "[clang][Fuchsia] Re-enable compiler-rt tests in runtimes build"

This reverts commit 95f824a.

We should've addressed the remaining issues on our CI builders.

Author: PiJoules

clang/cmake/caches/Fuchsia-stage2.cmake

@@ -120,6 +120,7 @@ foreach(target aarch64-unknown-linux-gnu;armv7-unknown-linux-gnueabihf;i386-unkn
     set(RUNTIMES_${target}_CMAKE_MODULE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(RUNTIMES_${target}_CMAKE_EXE_LINKER_FLAGS "-fuse-ld=lld" CACHE STRING "")
     set(RUNTIMES_${target}_COMPILER_RT_USE_BUILTINS_LIBRARY ON CACHE BOOL "")
+    set(RUNTIMES_${target}_COMPILER_RT_CAN_EXECUTE_TESTS ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_ENABLE_SHARED OFF CACHE BOOL "")
     set(RUNTIMES_${target}_LIBUNWIND_USE_COMPILER_RT ON CACHE BOOL "")
     set(RUNTIMES_${target}_LIBCXXABI_USE_COMPILER_RT ON CACHE BOOL "")