Port all babel-parser changes from 2018-05-18 to 2018-07-09

[alangpierce]

Changes in chronological order:

daf0ca868 Rename "babylon" to "@babel/parser" (#7937) 🎉
🚫 Not relevant for sucrase.

51eef099b fixes [skip ci]
🚫 Docs only.

0879a6d60 Subsume json (#7985)
✅ We already skipped the relevant newline check, so no porting needed for
correctness, but I removed the unused function.

c558dedd7 fix typo of babel in readme (#7992) [skip ci]
🚫 Docs only.

442ead701 Fix a few out-of-order test results.
🚫 Tests only.

2058e0686 Add support for an InterpreterDirective AST node.
🚫 I could add the new token type, but doesn't seem worth it.

981bff08e Fix some flow issues in @babel/parser flow plugin (#8002)
🚫 Just types changes.

ad1de09b5 docs: [skip ci] update AST spec
🚫 Docs only.

7d99a96f9 docs: [skip ci] add InterpreterDirective
🚫 Docs only.

b33823e7f Better error message for invalid decorators syntax (#7986)
🚫 Only changed error handling.

ffe04d919 [babylon] Refactor mixin plugins handling & validation (#7999)
🚫 Sucrase doesn't use any of the plugin code anymore.

c992f5b61 Remove duplicated test (in the old babylon folder)
🚫 Test only.

a94cbf760 Set exprAllowed to false when parsing TSNonNullExpression (#7968)
🚫 We aren't using exprAllowed anymore, bug doesn't seem to manifest.

555ee80f4 Fix some ts test fixtures
🚫 Test only.

6eab6f586 [Babylon] Take the first set of options for plugins (#7994)
🚫 Plugins not used in Sucrase.

e6d198eef v7.0.0-beta.48
🚫 Release only.

90566103a v7.0.0-beta.49
🚫 Release only.

f0283572a Support Flow's proto modifier syntax for declared classes (#7978)
✅ Added a new proto contextual token type and the parsing details for it.

f699f1bbb flow@0.73.0 (#8032)
🚫 Just a tooling upgrade.

2a8ebbe7a Remove parenthesizedArgument (#7981)
🚫 Not relevant to sucrase.

d83d141e0 Move tests from babylon/ to babel-parserr/
🚫 Test only.

fe556c502 fix folder name (#8074)
🚫 Test only.

b8dcd6f59 Remove parser support for decorators optional parentheses (#8037)
🚫 Parsing appears to be the same for Sucrase.

5895277b3 Bump prettier to v1.13.2
🚫 Formatting only.

b445b7973 Refactor move docs (#8108)
🚫 Docs only.

8bbb10c02 chore: [skip ci] regen READMEs
🚫 Docs only.

6349118be Change decoratorsBeforeExport default to false (#8113)
🚫 Only error message change.

218d69007 Merge pull request #8112 from babel/feat-add-issues-link-in-readmes
🚫 Docs only.

6480ae4a9 fix flow-double-nullable-type-cant-be-parsed
✅ Slightly different state representation, but both work.

bd4490202 update fixture
🚫 Test only.

62eb32677 ECMAScript follows the latest version of the Unicode Standard. Earlier this week, Unicode v11 was officially released. This patch updates babel-parser to support the new identifier characters. (#8125)
✅ Updated regexes, although maybe we should remove them at some point.

8070a2204 Link to open issues in READMEs [skip ci]
🚫 Docs only.

b6455c611 Allow ts modifier names to be used as function argument names (#8030)
✅ Added test, which failed, and bug fix fixed the test.

106907e60 fix: import Parser as type (#8146) [skip ci]
🚫 Not relevant in Sucrase.

3af623678 v7.0.0-beta.50
🚫 Release only.

c313b267f v7.0.0-beta.51
🚫 Release only.

ca6578113 @babel/parser: expose a TypeScript definition file from package This allows the new parser package to be used in TypeScript projects, with static type checking and auto-completions. IDEs like VSCode will use this to show auto completions even in JavaScript projects, which is a huge benefit to users wanting to use the parser directly.
🚫 Types only.

adbf2a15f Clearer naming of interfaces
🚫 Types only.

4cdfee768 Add jsdocs to parse() and parseExpression() also change parameter name to match docs
🚫 Types only.

0e8830f3a Fix unneeded uppercasing in comment
🚫 Types only.

ba98cf782 Removed constant condition in parser (#8177)
🚫 Not in Sucrase.

07c88e6f0 Use charCodes at more places in the parser (#8176)
🚫 I'd rather not change the identifier ones because I want it to be obvious
that the numbers are increasing.

8f8b4e8e8 Switch new website in READMEs (#8181) [skip ci]
🚫 Docs only.

e86d1e0d6 babel/parser: test helpers: write expected throw message to options.json ~ complete jest -u functionality (#8178) [skip ci]
🚫 Tests only.

c6a4108e5 Update READMEs for yarn (#8215) [skip ci]
🚫 Docs only.

db1385fb8 upgrades eslint v5 (major), babel-eslint, eslint-plugin-flowtype, eslint-plugin-prettier (#8259)
🚫 Tools only.

663c96db0 v7.0.0-beta.52
🚫 Release only.

19a170529 Support pipeline proposal flag in @babel/parser (#8291)
🚫 Config change only.