As a special case, multi-line raw strings (i.e., strings in `` quotes)
were not indented if they were the only token on a line. This heuristic
was meant to improve formatting for multi-line raw strings where sub-
sequent lines are not indented at the level of the surrounding code.
Multiple people have complained about this. Removing the heuristic
again because it makes the formatting more regular, easier to under-
stand, and simplifies the implementation.

- manual changes to ebnf/ebnf_test.go for readability
- gofmt -w src misc

Fixes #1643.

R=r, rsc
CC=golang-dev
https://golang.org/cl/4307045