Error compiling libraries

[nicholaspai]

Describe the bug
The following error is thrown when compiling libraries:

OVM Compiler Error (insert "// @unsupported: ovm" if you don't want this file to be compiled for the OVM):
 InternalCompilerError: Assembly exception for bytecode


Error HH600: Compilation failed

To Reproduce
Steps to reproduce the behavior:

1. Library contract to compile:

library TestLibrary {
    function returnBool() internal pure returns (bool) {
        return true;
    }
}

2. hardhat compile --network optimism --show-stack-traces
3. If you change the library keyword to contract, it should compile correctly.

Expected behavior
Libraries should compile to OVM AFAIK

System Specs:

• OS: macOS 11.4
• Package Version (or commit hash): @eth-optimism/hardhat-ovm@^0.2.2

[nicholaspai]

Related to #23