tests: Use a static parse context for tests

tests: Use a static token location for random tokens

tests: Use static tokens with static locattions

tests: Use static token location for tokenizer test

parse: Reserve keywords for reference names

tests: Move whitespace code to test_tokenize ...

The parser doesn't have to worry about whitespace, so it's not worth
worrying about it here.

tests: Add garbled strategy for draw_token_random

src: Rename syntax to token