[CMake][Fuchsia] Enable experimental pass manager by default

[phosek]

Summary

We plan on using experimental new pass manager for Fuchsia toolchain.

[leonardchan]

This comment was removed by leonardchan.

cfe/trunk/cmake/caches/Fuchsia-stage2.cmake

 set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
 if(NOT APPLE)
   set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
   set(CLANG_DEFAULT_OBJCOPY llvm-objcopy CACHE STRING "")
 endif()
 set(CLANG_DEFAULT_RTLIB compiler-rt CACHE STRING "")
 set(CLANG_PLUGIN_SUPPORT OFF CACHE BOOL "")
 
+set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER ON CACHE BOOL "")
 set(ENABLE_LINKER_BUILD_ID ON CACHE BOOL "")
 set(ENABLE_X86_RELAX_RELOCATIONS ON CACHE BOOL "")
 
 set(CMAKE_BUILD_TYPE RelWithDebInfo CACHE STRING "")
 set(CMAKE_C_FLAGS_RELWITHDEBINFO "-O3 -gline-tables-only" CACHE STRING "")
 set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-O3 -gline-tables-only" CACHE STRING "")
 
 if(APPLE)

cfe/trunk/cmake/caches/Fuchsia.cmake

 set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
 if(NOT APPLE)
   set(CLANG_DEFAULT_LINKER lld CACHE STRING "")
   set(CLANG_DEFAULT_OBJCOPY llvm-objcopy CACHE STRING "")
 endif()
 set(CLANG_DEFAULT_RTLIB compiler-rt CACHE STRING "")
 set(CLANG_PLUGIN_SUPPORT OFF CACHE BOOL "")
 
+set(ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER ON CACHE BOOL "")
 set(ENABLE_LINKER_BUILD_ID ON CACHE BOOL "")
 set(ENABLE_X86_RELAX_RELOCATIONS ON CACHE BOOL "")
 
 set(LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
 set(CMAKE_BUILD_TYPE Release CACHE STRING "")
 
 if(APPLE)
   set(COMPILER_RT_ENABLE_IOS OFF CACHE BOOL "")