Remove unused leading_zero_possible field from phonemetadata.proto

Deleted all methods that refer to this.
Regenerated jars - because we no longer write a boolean for the removed proto field, all the java metadata files needed regenerating too.

* Added new classes with behavior from MetadataManager & MetadataSource

* Replaced MetadataManager usages with new classes

* New PrefixDataIOHandler which packs data into a jar

* Added mockito-core jar to lib folder

* Added mockito-all jar to lib folder and updated tests to not use junit4 annotations

* Fixed prefix generation entry points

* Specific exception for missing metadata cases

* Small change in checking missing metadata cases

* ShortNumberInfo metadata tooling - add missing fields to generated JSON.

Adjust javascript metadata generation tooling to include PhoneMetadata proto fields 29,30,31, and 33 that were previously excluded which are now needed for ShortNumberInfo.

* Add shortnumberinfo metadata to build metadata golden tests.

* Remove inaccurate comments in build tooling

* Add namespace to BuildMetadataJsonFromXml to support tool reuse

* Use updated build tooling to generate short number metadata file

* update phonemetadata.pb.js to match the current proto definition

* remove field 7 from phonemetadata.pb.js

* Update build tool to correctly namespacee the generated metadata files

* Stop field 32 from being populated as it is not used in the APIs

* remove metadata accessors for field 32.

* Add tests for connectsToEmergenyNumber and isEmergencyNumber.

Updated linter to include shortnumberinfo related files, and fixed some
lint issues existing with PhoneNumberUtil files.

* ShortNumberInfo functionality and tests ported. Unformatted and missing jsdoc

* Added comments, and fixed as many lint issues as possible.

* lint and comment review comments from andyst addressed.

* Add a golden metadata build test for short number metadata.

* Revert changes to the original phone metadata golden tests.

* Fix a lot of linting and jsdoc typing errors caught by the compiler.

* Add ShortNumberInfo to the javascript demo pages.

* Add ShortNumberIInfo porting to pending_code_changes.

* Add constants to golden tests.

* Update the build tooling

* uUdate pending changes to differentiate build and code changes

* Update build file, fix small test closure compilation issues

* Regenerate short number metadata to account for metadata updates between original generation and now.

* Move requires to alphabetical order

*   It was confusing and unnecessary. Not every country that has short numbers beginning with a 0 had it, and it is not the only digit that could overlap with a national prefix and hence be interpreted incorrectly.

1) Changing the BuildMetadataFromXml to only set
same_mobile_and_fixed_line_pattern and
national_prefix_optional_when_formatting if they differ from default
values, and the domestic_carrier_code_formatting_rule,
international_prefix and national_prefix_formatting_rule if there is
one.

2) Adding a test with some golden data for the BuildMetadataJsonFromXml.

3) Adding to the proto a missing explicit default false.

4) Updating a couple of methods in the Phonemetadata.java class to have
names that match those of the auto-generated Phonemetadata used by the
CPP build, now that we use those methods when building the metadata.

5) Fix to ant build file to enable the junit command to still work (instructions on open-source on how to regenerate metadata files refer to this)

Resulting data is smaller for Java and C++ and the resulting BuildMetadataJsonFromXml code is cleaner.