libgo: avoid use of 'local' directive in shell script

Avoid declaring shell variables with 'local' (not supported
    on all systems of interest).
    
    Reviewed-on: https://go-review.googlesource.com/c/145021

From-SVN: r265534

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-ad50884d2a4b653f7f20edc8b441fe6ad6570d55
+9785e5c4e868ba55efdb33fc51872b4821770167
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/testsuite/gotest

@@ -513,9 +513,7 @@ localname() {
 #    Returned:          leaf.Mumble
 #
 symtogo() {
-  local s=""
-  local result=""
-  local ndots=""
+  result=""
   for tp in $*
   do
     s=$(echo "$tp" | sed -e 's/\.\.z2f/%/g' | sed -e 's/.*%//')