[ruby/prism] Prism.parse_success?(source)

A lot of tools use Ripper/RubyVM::AbstractSyntaxTree to determine
if a source is valid. These tools both create an AST instead of
providing an API that will return a boolean only.

This new API only creates the C structs, but doesn't bother
reifying them into Ruby/the serialization API. Instead it only
returns true/false, which is significantly more efficient.

7014740118

test/prism/ruby_api_test.rb

@@ -20,6 +20,18 @@ module Prism
       assert_equal_nodes ast2, ast3
     end
 
+    def test_parse_success?
+      assert Prism.parse_success?("1")
+      refute Prism.parse_success?("<>")
+
+      assert Prism.parse_success?("m //", verbose: false)
+      refute Prism.parse_success?("m //", verbose: true)
+    end
+
+    def test_parse_file_success?
+      assert Prism.parse_file_success?(__FILE__)
+    end
+
     def test_options
       assert_equal "", Prism.parse("__FILE__").value.statements.body[0].filepath
       assert_equal "foo.rb", Prism.parse("__FILE__", filepath: "foo.rb").value.statements.body[0].filepath