Add tests for instruction sizes

In short: add to test_script_type_size.ml tests checking that for each instruction it's size estimated by the interpreter is not too far from what is computed by Obj.reacahble_words.

The following discussion from !4731 (merged) should be addressed:

• @yrg started a discussion: (+3 comments)

  It is now the time to extend lib_protocol/test/integration/michelson/test_script_ir_size with an enumeration of all the instructions, checking that the model is not far from Obj.reachable_words.