Switch to heredoc for new ImportStatement tests
Switch to heredoc for new ImportStatement tests

Pointed out by @lencioni
https://github.com/trotzig/import-js/commit/73bce8a0c725798cbf5e089b4ba0fc8c32dcb81d#commitcomment-16401889

Also added a missing equals sign.

I reverted ImportStatement temporarily to make sure that these tests
still expose the same set of bugs.

trotzig/import-js,Galooshi/import-js,trotzig/import-js,trotzig/import-js