libgo: update to go1.7rc3

Reviewed-on: https://go-review.googlesource.com/25150

From-SVN: r238662

libgo/go/regexp/syntax/compile.go

@@ -8,11 +8,11 @@ import "unicode"
 
 // A patchList is a list of instruction pointers that need to be filled in (patched).
 // Because the pointers haven't been filled in yet, we can reuse their storage
-// to hold the list.  It's kind of sleazy, but works well in practice.
+// to hold the list. It's kind of sleazy, but works well in practice.
 // See http://swtch.com/~rsc/regexp/regexp1.html for inspiration.
 //
 // These aren't really pointers: they're integers, so we can reinterpret them
-// this way without using package unsafe.  A value l denotes
+// this way without using package unsafe. A value l denotes
 // p.inst[l>>1].Out (l&1==0) or .Arg (l&1==1).
 // l == 0 denotes the empty list, okay because we start every program
 // with a fail instruction, so we'll never want to point at its output link.