Bugs in the LLL code snippets of the testing suite

[axic]

This is a follow up of #3356.

I've run the code snippets through a stricter lllc (see ethereum/solidity#1313) and it has found a lot of potential buggy lll snippets: https://gist.github.com/axic/c245b7d7f1a3896282de77e69d2f568d

Issues:

• unterminated code (missing ) or })
• using missing instructions (SAWP1 vs. SWAP1, potentially archaic ones: PREVHASH, POST, CALLSTATELESS, CALLVALUE)
• using asm without ()

Some of the bugs might be false positive (such as MSIZE and the missing i variable, have to investigate).

[axic]

After review:

• I assume POST is an old name for CALL?
• CALLSTATELESS is an old name for CALLCODE?
• PREVHASH was replaced by 1 NUMBER SUB BLOCKHASH?
• CALLVALUE and MSIZE are methods and must be called or wrapper in an assembly block:
  (CALLVALUE) or (asm CALLVALUE).