create_test_sourcelist: Initialize variable at declaration

Clang -Wconditional-uninitialized warns otherwise.
Remove 'return' statements that can never be reached

Clang -Wunreachable-code-return warns otherwise.
Merge topic 'clang-warnings' into next

8c9c4fe1 Remove 'return' statements that can never be reached
50ca77f4 create_test_sourcelist: Initialize variable at declaration