Remove unnecessary cache

[k163377]

SSIA

Like #627, this change also mitigates #584.

[k163377]

The Class -> KClass conversion is cached on the Kotlin side as of 1.5.32, so there is no need to cache it in jackson-module-kotlin anymore.
https://github.com/JetBrains/kotlin/blob/v1.5.32/core/reflection.jvm/src/kotlin/reflect/jvm/internal/kClassCache.kt

[k163377]

This cache was no longer being used.

[cowtowncoder]

I don't usually handle review here, but this makes sense to me so +1.

[k163377]

@cowtowncoder
It appears that the merge is causing a METHOD_REMOVED error.
Could you please tell me how to resolve this error?
https://github.com/FasterXML/jackson-module-kotlin/actions/runs/4215048499/jobs/7315912740

[cowtowncoder]

@k163377 I did not set it up, but Maven plugin "japicmp-maven-plugin" was recently set up to guard against API compatibility changes by maintainers (I think @dinomite remembers this) -- alas, release notes haven't been kept up to date so I don't see the PR/issue number.
But it's this in pom.xml:

            <plugin>
                <groupId>com.github.siom79.japicmp</groupId>
                <artifactId>japicmp-maven-plugin</artifactId>

The idea being it flags anything that even theoretically breaks backwards-compatibility -- and removal of a protected field is theoretically such thing (since someone could have sub-classed class, referenced field).
In practice there are cases where such changes should be made, I think; and for that we have to add exclusions to basically tell "that's ok, don't worry about the change".
These are added under:

                    <parameter>
                        <breakBuildOnBinaryIncompatibleModifications>true</breakBuildOnBinaryIncomp\
atibleModifications>
                        <breakBuildOnSourceIncompatibleModifications>true</breakBuildOnSourceIncomp\
atibleModifications>
                        <excludes>
                           <exclude>com.fasterxml.jackson.module.kotlin.ValueClassBoxSerializer</exclude>
                           ....
                        </excludes>

so you will probably need to add one or more excludes. I went and removed ones that were left over from 2.13 -> 2.14 cases.

[cowtowncoder]

@k163377 I was able to reproduce the issue and add exclusion to basically disable compatibility check for ReflectionCache class.

To get this check to run locally you need to call verify target, so like:

./mvnw clean verify

since install will not run it.