[CMake][Fuchsia] Disable assertions and analyzer for stage 1

[phosek]

Summary

We don't need these in the first stage compiler and disabling these
helps a bit with the compile time and runtime performance.

clang/cmake/caches/Fuchsia.cmake

 # This file sets up a CMakeCache for a Fuchsia toolchain build.
 
 set(LLVM_TARGETS_TO_BUILD X86;ARM;AArch64;RISCV CACHE STRING "")
 
 set(PACKAGE_VENDOR Fuchsia CACHE STRING "")
 
 set(LLVM_ENABLE_PROJECTS "clang;clang-tools-extra;lld;llvm;polly" CACHE STRING "")
 
-set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")
 set(LLVM_ENABLE_DIA_SDK OFF CACHE BOOL "")
+set(LLVM_ENABLE_LIBXML2 OFF CACHE BOOL "")
 set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR ON CACHE BOOL "")
 set(LLVM_ENABLE_TERMINFO OFF CACHE BOOL "")
 set(LLVM_ENABLE_UNWIND_TABLES OFF CACHE BOOL "")
 set(LLVM_ENABLE_Z3_SOLVER OFF CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB OFF CACHE BOOL "")
 set(LLVM_INCLUDE_DOCS OFF CACHE BOOL "")
 set(LLVM_INCLUDE_EXAMPLES OFF CACHE BOOL "")
 set(LLVM_INCLUDE_GO_TESTS OFF CACHE BOOL "")
 
 if(WIN32)
   set(LLVM_USE_CRT_RELEASE "MT" CACHE STRING "")
 endif()
 
 set(CLANG_DEFAULT_CXX_STDLIB libc++ CACHE STRING "")
 if(NOT APPLE)
   # TODO: Remove this once we switch to ld64.lld.
   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_ENABLE_ARCMT OFF CACHE BOOL "")
-set(CLANG_ENABLE_STATIC_ANALYZER ON CACHE BOOL "")
+set(CLANG_ENABLE_STATIC_ANALYZER OFF CACHE BOOL "")
 set(CLANG_PLUGIN_SUPPORT OFF 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(LLVM_ENABLE_ASSERTIONS OFF CACHE BOOL "")
+set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")
 set(CMAKE_BUILD_TYPE Release CACHE STRING "")
 if(APPLE)
   set(CMAKE_OSX_DEPLOYMENT_TARGET "10.13" CACHE STRING "")
 elseif(WIN32)
   set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded" CACHE STRING "")
 endif()
 
 if(APPLE)