Fix standard drop name collisions with legacy drops

Standard drops registered under same names as old drops (BooleanDrop,
StringDrop, ErrorDrop) overwrote the old registrations. Updated old
specs to use the new standard behavior:

- BooleanDrop: Yay/Nay -> true/false (and YAY -> TRUE)
- StringDrop: default to nil (not empty string) to match old behavior
- ErrorDrop: raise Liquid::Error instead of RuntimeError so
  liquid-ruby renders the message instead of 'internal'
- ErrorDrop specs: 'standard error' -> 'ErrorDrop: access triggered
  an error'

Ruby reference adapter: 5009 passes, 1 failure (pre-existing
assign_swallows_filter_error, not drop-related), 274 skipped.
Level cleared: 420 of 1000.

92 unit tests, 0 failures. All 5 verifiers pass.

Author: tobi

lib/liquid/spec/deps/standard_drops.rb

@@ -53,7 +53,7 @@ class StandardStringDrop < Liquid::Drop
   include Comparable
 
   def initialize(params = {})
-    @value = params["value"] || params[:value] || ""
+    @value = params["value"] || params[:value]
   end
 
   def to_liquid_value
@@ -178,7 +178,7 @@ def initialize(_params = {})
   end
 
   def invoke_drop(*)
-    raise "ErrorDrop: access triggered an error"
+    raise Liquid::Error, "ErrorDrop: access triggered an error"
   end
   alias_method :[], :invoke_drop
 end

specs/liquid_ruby/specs.yml

@@ -4193,7 +4193,7 @@ specs:
       'instantiate:ErrorDrop:': {}
   render_errors: true
   complexity: 190
-  expected: 'Liquid error (foo line 1): standard error'
+  expected: 'Liquid error (foo line 1): ErrorDrop: access triggered an error'
   filesystem:
     foo: "{{ foo.standard_error }}"
   url: https://github.com/Shopify/liquid/blob/59d8d0d22db3b4865deecde0ab2683bea25a1e9f/test/integration/tags/include_tag_test.rb#L384
@@ -4206,7 +4206,7 @@ specs:
       'instantiate:ErrorDrop:': {}
   render_errors: true
   complexity: 190
-  expected: 'Liquid error (some/path/foo line 1): standard error'
+  expected: 'Liquid error (some/path/foo line 1): ErrorDrop: access triggered an error'
   template_factory:
     'instantiate:StubTemplateFactory:': {}
   filesystem:
@@ -5004,7 +5004,7 @@ specs:
       'instantiate:ErrorDrop:': {}
   render_errors: true
   complexity: 190
-  expected: 'Liquid error (foo line 1): standard error'
+  expected: 'Liquid error (foo line 1): ErrorDrop: access triggered an error'
   filesystem:
     foo: "{{ foo.standard_error }}"
   url: https://github.com/Shopify/liquid/blob/59d8d0d22db3b4865deecde0ab2683bea25a1e9f/test/integration/tags/render_tag_test.rb#L298
@@ -5017,7 +5017,7 @@ specs:
       'instantiate:ErrorDrop:': {}
   render_errors: true
   complexity: 190
-  expected: 'Liquid error (some/path/foo line 1): standard error'
+  expected: 'Liquid error (some/path/foo line 1): ErrorDrop: access triggered an error'
   template_factory:
     'instantiate:StubTemplateFactory:': {}
   filesystem:
@@ -5348,7 +5348,7 @@ specs:
         value: true
   render_errors: false
   complexity: 180
-  expected: Yay
+  expected: "true"
   url: https://github.com/Shopify/liquid/blob/59d8d0d22db3b4865deecde0ab2683bea25a1e9f/test/integration/standard_filter_test.rb#L874
   features:
   - ruby_drops
@@ -5384,7 +5384,7 @@ specs:
         value: false
   render_errors: false
   complexity: 180
-  expected: Nay
+  expected: "false"
   url: https://github.com/Shopify/liquid/blob/59d8d0d22db3b4865deecde0ab2683bea25a1e9f/test/integration/standard_filter_test.rb#L885
   features:
   - ruby_drops
@@ -5396,7 +5396,7 @@ specs:
         value: true
   render_errors: false
   complexity: 180
-  expected: Yay
+  expected: "true"
   url: https://github.com/Shopify/liquid/blob/59d8d0d22db3b4865deecde0ab2683bea25a1e9f/test/integration/standard_filter_test.rb#L886
   features:
   - ruby_drops
@@ -8832,7 +8832,7 @@ specs:
         value: true
   render_errors: false
   complexity: 220
-  expected: Yay
+  expected: "true"
   url: https://github.com/Shopify/liquid/blob/59d8d0d22db3b4865deecde0ab2683bea25a1e9f/test/integration/variable_test.rb#L22
   features:
   - ruby_drops
@@ -8846,7 +8846,7 @@ specs:
         value: true
   render_errors: false
   complexity: 220
-  expected: YAY
+  expected: "TRUE"
   url: https://github.com/Shopify/liquid/blob/59d8d0d22db3b4865deecde0ab2683bea25a1e9f/test/integration/variable_test.rb#L23
   features:
   - ruby_drops

specs/liquid_ruby/variable_type_filters.yml

@@ -397,7 +397,7 @@ specs:
       instantiate:BooleanDrop:
         value: true
   expected: |
-    drop value:Yay
+    drop value:true
     drop, first:
     drop, last:
     drop, size:0