go/types: replace invalid(AST|Arg|Op) with errorf and message prefix

go/types: replace invalid(AST|Arg|Op) with errorf and message prefix

This brings go/types error reporting closer to types2.

Except for removing the error functions and one manual correction,
these changes were made by regex-replacing:

check\.invalidAST\((.*), "      =>
check.errorf($1, InvalidSyntaxTree, invalidAST+"

check\.invalidOp\((.*), "       =>
check.errorf($1, invalidOp+"

check\.invalidArg\((.*), "      =>
check.errorf($1, invalidArg+"

A follow-up CL ensures that we use error instead of errorf where
possible.

Change-Id: Iac53dcd9c122b058f98d26d0fb307ef1dfe4e79b
Reviewed-on: https://go-review.googlesource.com/c/go/+/441955
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>