AAPT2: Fix unrecognized CDATA

This change adds support for resources that have CDATA blocks within
their values. The blocks should allow any character to occur without
being escaped. It also should not effect the current state of quote
processing.

Bug: 80326349
Test: Created tests in aapt2_tests
Change-Id: Ie1a00e50cffc877e2eb5f788f8d7a1bda839c0cf