Update unit tests for -dump-function-declarations

- Apply -dump-function-declarations to input/*.h.
- Add an explicitly deleted function to input/example1.h.
- Remove gen_expected_output.py and input/func_decl_*.h.

Bug: 71485848
Bug: 117582158
Test: ./test.py
Change-Id: Ic81448a3607c23bfb10781b4df097578814b7118