opcodes.ts is now implicit-any-clean.
Miscellaneous typing.
Pretty sure that if check was unnecessary.
Improve typing for jvm.ts.

There seems to be a TypeScript bug where some types are not inferred
when certain syntax quirks are present. For example, when passing a
function expression as parameter, adding parentheses around it seems to
confuse the compiler. Likewise with the `return` in `return function()
{...}`.
Improve typing of disassembler.
ConstantPool is now implicit-any-free.
attributes.ts is now implicit-any-free.
Misc typing.
Get coverage.ts working again.

Also add types to coverage.ts and testing.ts. The former is now
implicit-any-free.