[schema] improve normalization of RQLExpressions Parse and print back the expression instead of manipulating the string. Among other benefits, it means we don't mangle embedded string constants that contain commas or multiple spaces. Closes #6694426

from os.path import join
assert __file__.endswith(join('scripts', 'script3.py')), __file__
assert '__main__' == __name__, __name__
assert ['-vd', '-f', 'FILE.TXT'] == __args__, __args__