Disable unnecessary io.cache=true in tests

[XVilka]

Your checklist for this pull request

• I've read the guidelines for contributing to this repository
• I made sure to follow the project's coding style
• I've added tests that prove my fix is effective or that my feature works (if possible)
• I've updated the documentation and the rizin book with the relevant information (if needed)

Detailed description

Now that binary loading uses virtual files, some of the io.cache=true calls in our tests are unnecessary. Remove them.

Test plan

CI is green

[wargio]

some tests has failed.

[XVilka]

@wargio @thestr4ng3r should be green now.

[wargio]

@wargio @thestr4ng3r should be green now.

nope.

[XVilka]

@wargio OpenBSD failure is unrelated:

rz-test(29988) in free(): chunk is already free 0xc8bc8097500
.tasks/test: line 18: 29988 Abort trap              (core dumped) MALLOC_OPTIONS=S rz-test -L -o results.json

[officialcjunior]

Would be great if someone added a oneliner about what io.cache does on the book's corresponding page, since you guys clearly know what it does.