ParsedSyntaxBuilder has a convenient function to add member to a syntax-collection
child. The function name uses the type name of the collection's members,
which can lead to name collision. This patch renames it.
This eliminates the overhead of ParsedRawSyntaxNode needing to do memory management.
If ParsedRawSyntaxNode needs to point to some data the memory is allocated from a bump allocator.
There are also some improvements on how the ParsedSyntaxBuilders work.
Doing a "direct ParsedSyntaxRecorder::record[some syntax]" call from the parser is not a good idea due to possibility
of being in a backtracking context when the call is made. Replace them with "ParsedSyntaxRecorder::make[some syntax]"
which will implicitly check for backtracking and create a recorded or deferred node accordingly.
Instead of creating syntax nodes directly, modify the parser to invoke an abstract interface 'SyntaxParseActions' while it is parsing the source code.
This decouples the act of parsing from the act of forming a syntax tree representation.
'SyntaxTreeCreator' is an implementation of SyntaxParseActions that handles the logic of creating a syntax tree.
To enforce the layering separation of parsing and syntax tree creation, a static library swiftSyntaxParse is introduced to compose the two.
This decoupling is important for introducing a syntax parser library for SwiftSyntax to directly access parsing.
