Fix memory leak for incomplete lambdas

	[Bug #19836]

	The parser does not free the chain of `struct vtable`, which causes
	memory leaks.

	The following script reproduces this issue:

	```
	10.times do
	  100_000.times do
	    Ripper.parse("-> {")
	  end

	  puts `ps -o rss= -p #{$$}`
	end
	```
	---
	 parse.y                    | 24 ++++++++++++++----------
	 test/ripper/test_ripper.rb |  7 +++++++
	 2 files changed, 21 insertions(+), 10 deletions(-)

	Fix memory leak in parser for incomplete tokens

	[Bug #19835]

	The parser does not free the `tbl` of the `struct vtable` when there are
	leftover `lvtbl` in the parser. This causes a memory leak.

	The following script reproduces this issue:

	```
	10.times do
	  100_000.times do
	    Ripper.parse("class Foo")
	  end

	  puts `ps -o rss= -p #{$$}`
	end
	```
	---
	 parse.y                    | 42 ++++++++++++++++++++++++++++--------------
	 test/ripper/test_ripper.rb |  7 +++++++
	 2 files changed, 35 insertions(+), 14 deletions(-)

* parse.y (parser_token_value_print): in ripper, ID values are
  wrapped in NODE_RIPPER at set_yylval_name(), so print the Symbol
  wrapped together.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67305 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* parse.y (ripper_state): add states of scanner to tokens from
  Ripper.lex and Ripper::Filter#on_*.  based on the patch by
  aycabta (Code Ahss) at [ruby-core:81789].  [Feature #13686]

* ext/ripper/tools/preproc.rb (prelude, usercode): generate EXPR_*
  constants from enums.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59896 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57538 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* parse.y (ripper_initialize): allow generic input as source, if
  it has #gets method.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57022 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56270 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56260 b2dd03c8-39d4-4d8f-98ff-823fe69b080e