Adds openapi v3.0.3 unit test spec, includes test cases, autogenerates model tests with them (#12619)

* Adds draft6 tests and python file reader

* Adds processing of multiple files

* Moves test examples into a different component so component schemas can be booleans

* Excludes boolean schema cases and some others that contain patternProperties

* Adds automatic test generation, template not quite working with indentation

* Turns on allOf tests, some failing

* Adds more generated components and tests

* Adds enum tests

* Turns on all of themissing tests

* Adds exclmax and min exclusion reasons

* Adds items test cases

* Adds maximum

* Adds maxItems

* Adds maxLength

* Adds maxProperties

* Adds minimum

* Adds minItems

* Adds minLength

* Adds minProperties

* Adds multipleOf

* Adds not

* Adds oneOf

* Adds pattern

* Adds patternProperties

* Working on properties examples, partial fix for escaped characters

* Further improves example string escaping

* Fixes properties test cases

* Adds draft6 test samples license

* Adds ref

* Finishes ref

* Adds remoteRef

* Adds required

* Improves required testing

* Fixes build error / javadoc warning

* Fixes uniqueItems bug in python-experimental

* Turns all tests back on

* Fixes 2 failing tests, all python tests pass

* Fixes java npe errors

* Fixes formatting of tests, indentation fixed

* Test fase name fixed to toTestCaseName, docstring added to ObjectWithTypeBooleans

* Fixes typo

* Adds test deletion to samples generation, samples regenerated

* Updates python-exp unit test sample, includes new ref examples

samples/openapi3/client/petstore/python-experimental/docs/StringEnum.md

@@ -2,9 +2,7 @@
 
 Type | Description | Notes
 ------------- | ------------- | -------------
-typing.Union[str, None, ] | |  must be one of ["placed", "approved", "delivered", "single quoted", '''multiple
-lines''', '''double quote 
- with newline''', ]
+typing.Union[str, None, ] | |  must be one of ["placed", "approved", "delivered", "single quoted", "multiple\nlines", "double quote \n with newline", ]
 
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