[v2.37.0] Disabled checks are executed when XepPatchChecks: is empty

[krisso-rtb]

While upgrading ErrorProne from 2.36 to 2.37 we observed checks defined in

com.google.errorprone.scanner.BuiltInCheckerSuppliers.DISABLED_CHECKS

are surprisingly fired.
Our maven-compiler-plugin has config:

<arg>
    -Xplugin:ErrorProne \
    -XepPatchLocation:IN_PLACE \
    -XepPatchChecks:${errorprone.patchChecks} \
    -XepDisableAllChecks \
    -Xep:NullAway:ERROR \
    <!-- and our custom checkers: -->

where errorprone.patchChecks is a dynamically-provided Maven param.
When it's empty we have effectively:

    -XepPatchLocation:IN_PLACE \
    -XepPatchChecks: \
   ...

and tons of unwanted checks are executed, e.g. BooleanParameter or UnnecessarilyFullyQualified.

When we remove these two lines it's fine.

The issue does NOT exist in 2.36.

---

It might be added by #4699.
In ErrorProneAnalyzer a few suspicious changes were made, especially around emptiness of namedCheckers variable.

[Stephan202]

I filed #5102; would love to receive feedback on whether this fixes the issue for you.