getUsageOfPattern behaves inconsistently

[RunDevelopment]

While writing tests, I found that getUsageOfPattern behaves strangely around unknown functions.

The following test cases pass.

{
    code: `foo(/[a-zA-Z]\\w*/)`,
    results: [UsageOfPattern.whole],
},
{
    code: `foo({ pattern: /[a-zA-Z]\\w*/ })`,
    results: [UsageOfPattern.unknown],
},

Both should have the same result: unknown. We do not know how foo is implemented. It might use the regex as is or it might return its source.

[ota-meshi]

I made an incorrect change when I changed from isPartialPattern to getUsageOfPattern. I will fix this bug.