Fix aapt2 whitespace diffs from aapt(1)

CDATA blocks were being processed differently in aapt2 so this change
fixes aapt2 to not treat cdata blocks differently and still trime
whitespace.

Also, aapt did not process escapes when compiling xml files. This
change removes over-processing of xml text nodes.

All test strings are what aapt(1) would output.

Test: aapt2_tests
Bug: 124470332
Change-Id: I90ee0c1e5e9208f8a5c60cee93e3ba02712c9b2c