cmd/objdump: print full disassembly when testing with -v

It is helpful for debugging.

Change-Id: Idd566d312037420f8341fcf502a45410a8497798
Reviewed-on: https://go-review.googlesource.com/c/go/+/353878


Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/objdump/objdump_test.go

@@ -228,7 +228,7 @@ func testDisasm(t *testing.T, srcfname string, printCode bool, printGnuAsm bool,
 		}
 	}
 
-	if !ok {
+	if !ok || testing.Verbose() {
 		t.Logf("full disassembly:\n%s", text)
 	}
 }