Expand Rust test suite

[jethrogb]

rust-lang/rust#59136 made it possible to run the std unit test suite for SGX. There are additional tests that may be run:

• std documentation tests
• Compile & run tests from src/test

[jethrogb]

@Goirad is this done?

[Goirad]

I'm not sure about what this is exactly. std doctests is (part of?) the doctest issue, and I don't know what the other checkbox is referring to.