`toBe` parse failure should be ignored if we are planning to overwrite the value anyway

[nedtwigg]

Story:

• selfie sets a toBe correctly
• autoformatter reformats with + or something like that
• selfie can't parse the file anymore

Solution

• Most of all we should generate strings that don't reformatted, e.g. #406
• But if it happens, we should make it easy to nuke the string literal as long as we can find the other paren