Parent-Task:

• SR-9116 Windows Support

Issue Description:

A number of gyb tests (gyb --test) fail on Windows. It appears it was introduced by commit d57b41e which altered the behaviour of line directives to print paths with forward-slashes even on Windows. Two issues:

1. Doctests involving paths weren't changed to reflect the new behaviour. This breaks the tests that replace the real path with dummy filenames.

2. ExecutionContext.append_path sometimes adds unnecessary line directives. The path normalization occurs in a code branch which does not always execute. The sometimes-normalized path is then recorded in self.last_file_line. When append_text is later invoked, it (incorrectly) compares the sometimes-normalized path in self.last_file_line with the non-normalized file argument.