ARM64: Fix native builds

Rearrange sed lines to enable native builds for ARM64.

BUG=
R=jochen@chromium.org

Review URL: https://codereview.chromium.org/238543009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20806 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

build/standalone.gypi

@@ -55,8 +55,8 @@
                 '<!(uname -m | sed -e "s/i.86/ia32/;\
                                        s/x86_64/x64/;\
                                        s/amd64/x64/;\
-                                       s/aarch64/arm64/;\
                                        s/arm.*/arm/;\
+                                       s/aarch64/arm64/;\
                                        s/mips.*/mipsel/")',
             }, {
               # OS!="linux" and OS!="freebsd" and OS!="openbsd" and