Multiple bug fixes and enhancements for std regex

[stephenamar-db]

Implement namedGroups (which was missing from the first implementation)

• JS is tricky because you need to convert Python-style named groups (the only ones supported by RE2) to perl ones
• You need to manually find them due to the lack of clear API in the JDK

Align our implementation with jrsonnet implementations:

• return null if no match
• make fullmatch just partialmatch with anchors - it also allows us to share more code.

Fix the - problem with regexQuote in RE2 across the board

[stephenamar-db]

@JoshRosen at your convenience