fix _spawn_primitive to report error correctly (JuliaLang#34716)

Method `_spawn_primitive` in `process.jl` seems to be defining a local valiable that shadows the `error` method that it tries to use.
This renames the local variable to fix that.

base/process.jl

@@ -84,7 +84,7 @@ const SpawnIOs = Vector{Any} # convenience name for readability
  for io in stdio]
  handle = Libc.malloc(_sizeof_uv_process)
  disassociate_julia_struct(handle) # ensure that data field is set to C_NULL
- error = ccall(:jl_spawn, Int32,
+ err = ccall(:jl_spawn, Int32,
  (Cstring, Ptr{Cstring}, Ptr{Cvoid}, Ptr{Cvoid},
  Ptr{Tuple{Cint, UInt}}, Int,
  UInt32, Ptr{Cstring}, Cstring, Ptr{Cvoid}),
@@ -94,9 +94,9 @@ const SpawnIOs = Vector{Any} # convenience name for readability
  cmd.env === nothing ? C_NULL : cmd.env,
  isempty(cmd.dir) ? C_NULL : cmd.dir,
  uv_jl_return_spawn::Ptr{Cvoid})
- if error != 0
+ if err != 0
  ccall(:jl_forceclose_uv, Cvoid, (Ptr{Cvoid},), handle) # will call free on handle eventually
- throw(_UVError("could not spawn " * repr(cmd), error))
+ throw(_UVError("could not spawn " * repr(cmd), err))
  end
  pp = Process(cmd, handle)
  associate_julia_struct(handle, pp)