For each .cpp file in the test suite data, there is a .ast file that
represents the "known good" baseline of the parser result.
Each .cpp file goes through the parser, and the result of
invoking `ASTNode::dump()` on the root node is compared to the
baseline to find regressions.
We also check that there were no parser errors when parsing the .cpp
files.
This is similar to the LibJS test data that resides in
/home/anon/js-tests.
It's more convenient than storing the test programs as raw strings
in the code.
This commit removes the only 3rd party library (and its usages)
in serenity: puff, which is used for deflate decompression. and
replaces it with the existing original serenity implementation
in LibCompress. :^)
This should speed up pre-commit a bit as only files that are staged will
be processed, and clang-format and shellcheck are only invoked once, not
for every file. When no arguments are given (e.g. on CI), it still uses
'git ls-files'.
