Use the project's tmp dir for specs

spec/compiler/crystal/tools/init_spec.cr

@@ -5,7 +5,8 @@ require "ini"
 require "spec"
 require "yaml"
 
-BIN_CRYSTAL = File.expand_path("#{__DIR__}/../../../../bin/crystal")
+PROJECT_ROOT_DIR = "#{__DIR__}/../../../.."
+BIN_CRYSTAL = File.expand_path("#{PROJECT_ROOT_DIR}/bin/crystal")
 
 private def exec_init(project_name, project_dir = nil, type = "lib")
   args = ["init", type, project_name]
@@ -21,8 +22,8 @@ end
 # Creates a temporary directory, cd to it and run the block inside it.
 # The directory and its content is deleted when the block return.
 private def within_temporary_directory
-  tmp_path = "#{__DIR__}/crystal_init_spec_tmp_dir-#{rand(10_000)}"
-  Dir.mkdir(tmp_path)
+  tmp_path = "#{PROJECT_ROOT_DIR}/tmp/init_spec_tmp_dir-#{Process.pid}"
+  Dir.mkdir_p(tmp_path)
   begin
     Dir.cd(tmp_path) do
       yield