go/printer: replace multiline logic

This CL mostly deletes code.

Using existing position information is
just as good to determine if a new section
is needed; no need to track exact multi-
line information. Eliminates the need to
carry around a multiLine parameter with
practically every function.

Applied gofmt -w src misc resulting in only
a minor change to godoc.go. In return, a couple
of test cases are now formatted better.

Not Go1-required, but nice-to-have as it will
simplify fixes going forward.

R=rsc
CC=golang-dev
https://golang.org/cl/5706055

src/pkg/go/printer/printer.go

@@ -34,9 +34,6 @@ const (
 	unindent = whiteSpace('<')
 )
 
-// Use ignoreMultiLine if the multiLine information is not important.
-var ignoreMultiLine = new(bool)
-
 // A pmode value represents the current printer mode.
 type pmode int
 
@@ -1011,18 +1008,18 @@ func (p *printer) printNode(node interface{}) error {
 	// format node
 	switch n := node.(type) {
 	case ast.Expr:
-		p.expr(n, ignoreMultiLine)
+		p.expr(n)
 	case ast.Stmt:
 		// A labeled statement will un-indent to position the
 		// label. Set indent to 1 so we don't get indent "underflow".
 		if _, labeledStmt := n.(*ast.LabeledStmt); labeledStmt {
 			p.indent = 1
 		}
-		p.stmt(n, false, ignoreMultiLine)
+		p.stmt(n, false)
 	case ast.Decl:
-		p.decl(n, ignoreMultiLine)
+		p.decl(n)
 	case ast.Spec:
-		p.spec(n, 1, false, ignoreMultiLine)
+		p.spec(n, 1, false)
 	case *ast.File:
 		p.file(n)
 	default: