require SerializedProgram.from_bytes() is passed a valid clvm structure

[arvidn]

Purpose:

The Streamable protocol (normally) requires input passed to parse() and from_bytes() be equally valid input. The distinction is that parse() consumes input from a stream, whereas from_bytes() expects the complete byte buffer to represent the complete value to be consumed for the streamable type.

SerializedProgram is currently an exception to this, where there is no validation at all of the input passed to from_bytes(), whereas parse() does validate the input. In most normal production use, parse() is how SerializedPrograms are initialized (such as parsing a FullBlock from the network or database).

There are however a few tests where we initialize SerializedProgram with invalid input. This is a small tweak to correct this quirk, and fix the tests.

Current Behavior:

SerializedProgram.from_bytes(b"aaa") is valid.

New Behavior:

SerializedProgram.from_bytes(b"aaa") is not valid.

[coveralls-official]

Pull Request Test Coverage Report for Build 6620383299

• 9 of 9 (100.0%) changed or added relevant lines in 4 files are covered.
• 104 unchanged lines in 12 files lost coverage.
• Overall coverage decreased (-0.09%) to 90.083%

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Files with Coverage Reduction	New Missed Lines	%
chia/data_layer/dl_wallet_store.py	1	95.74%
chia/rpc/wallet_rpc_api.py	1	88.06%
chia/server/node_discovery.py	1	78.01%
chia/wallet/wallet_node.py	1	87.8%
chia/timelord/timelord_api.py	2	87.85%
chia/farmer/farmer_api.py	3	86.35%
chia/rpc/rpc_server.py	3	87.33%
chia/server/server.py	6	81.07%
chia/full_node/full_node.py	8	86.3%
chia/full_node/full_node_api.py	9	77.33%

Totals
Change from base Build 6616417205:	-0.09%
Covered Lines:	93077
Relevant Lines:	103270

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💛 - Coveralls