[Fuchsia] Add BOOTSTRAP_BOOTSTRAP flags for PGO (llvm#150448)

Author: gulfemsavrun

clang/cmake/caches/Fuchsia.cmake

@@ -76,6 +76,9 @@ foreach(variable ${_FUCHSIA_BOOTSTRAP_PASSTHROUGH})
     get_property(value CACHE ${variable} PROPERTY VALUE)
     get_property(type CACHE ${variable} PROPERTY TYPE)
     set(BOOTSTRAP_${variable} "${value}" CACHE ${type} "")
+    if(FUCHSIA_ENABLE_PGO)
+      set(BOOTSTRAP_BOOTSTRAP_${variable} "${value}" CACHE ${type} "")
+    endif()
   endif()
 endforeach()