cmd/objdump: update test with register ABI

With register ABI, the disassembly of the function may not
contain a "movq" instruction (which used to be e.g. storing
arguments to stack). Look for "jmp" instruction instead. This is
also in consistent with the test for Go assembly syntax.

Change-Id: Ifc9e48bbc4f85c4e4aace5981b3a0f8ae925f6d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/308652
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>

src/cmd/objdump/objdump_test.go

@@ -64,13 +64,13 @@ var x86Need = []string{ // for both 386 and AMD64
 }
 
 var amd64GnuNeed = []string{
-	"movq",
+	"jmp",
 	"callq",
 	"cmpb",
 }
 
 var i386GnuNeed = []string{
-	"mov",
+	"jmp",
 	"call",
 	"cmp",
 }