Removed OP_EQ signed versions as they're useless

A negative number under 2s complement can never be equal to its
positive as the top bit *must* be on.  If two numbers are equivalent
bit-by-bit then they are equal for both signed and unsigned numbers.

vm/runtime.c

@@ -55,7 +55,7 @@ const char *err_as_cstr(err_t err)
 
 err_t vm_execute(vm_t *vm)
 {
-  static_assert(NUMBER_OF_OPCODES == 73, "vm_execute: Out of date");
+  static_assert(NUMBER_OF_OPCODES == 70, "vm_execute: Out of date");
   struct Program *prog = &vm->program;
   if (prog->ptr >= prog->max)
     return ERR_END_OF_PROGRAM;