(PUP-11314) Guard on_initialize_and_write hooks

Puppet's test helper calls `initialize_app_defaults` before each test, which
calls all hooks of type `on_initialize_and_write`[1]. So we were requiring two
files unnecessarily about 26k times, which is really slow on Windows. Also we
were appending 2 paths to Facter's search path for each test in an unbounded
way. Note vardir is different for each test, so it's not possible to only add
paths we haven't seen before.

Note puppet.rb already required `puppet/node` outside the hook, so this just
adds a require for `puppet/node/facts`.

For loglevel, made the setter idempotent if the level is unchanged. Also avoid
scanning the array of log levels twice if an invalid level is given.

[1] https://github.com/puppetlabs/puppet/blob/7.11.0/lib/puppet/settings.rb#L390

Author: joshcooper

lib/puppet.rb

@@ -364,3 +364,4 @@ def self.runtime
 require 'puppet/file_bucket/file'
 require 'puppet/plugins/configuration'
 require 'puppet/pal/pal_api'
+require 'puppet/node/facts'

lib/puppet/defaults.rb

@@ -2050,7 +2050,9 @@ def self.initialize_default_settings!(settings)
       :call_hook => :on_initialize_and_write, # Call our hook with the default value, so we always get the value added to facter.
       :hook => proc do |value|
         paths = value.split(File::PATH_SEPARATOR)
-        Puppet.runtime[:facter].search(*paths)
+        facter = Puppet.runtime[:facter]
+        facter.reset
+        facter.search(*paths)
       end
     }
   )
@@ -2191,8 +2193,6 @@ def self.initialize_default_settings!(settings)
       # Call our hook with the default value, so we always get the libdir set.
       :call_hook => :on_initialize_and_write,
       :hook => proc do |value|
-        require 'puppet/node'
-        require 'puppet/node/facts'
         if value
           Puppet::Resource::Catalog.indirection.set_global_setting(:cache_class, :store_configs)
           settings.override_default(:catalog_cache_terminus, :store_configs)

lib/puppet/util/log.rb

@@ -105,9 +105,14 @@ def Log.level
   def Log.level=(level)
     level = level.intern unless level.is_a?(Symbol)
 
-    raise Puppet::DevError, _("Invalid loglevel %{level}") % { level: level } unless @levels.include?(level)
+    # loglevel is a 0-based index
+    loglevel = @levels.index(level)
+    raise Puppet::DevError, _("Invalid loglevel %{level}") % { level: level } unless loglevel
 
-    @loglevel = @levels.index(level)
+    return if @loglevel == loglevel
+
+    # loglevel changed
+    @loglevel = loglevel
 
     # Enable or disable Facter debugging
     Puppet.runtime[:facter].debugging(level == :debug)