jvm.ClassReader should set the accessor to the corresponding record component

A DESCRIPTION OF THE PROBLEM :
During annotation processing TypeElement#getRecordComponents returns empty list for Records which are located in another jar.

In Java 16.ea.28 TypeElement#getRecordComponents works correctly. However, the returned RecordComponentModel returns null for RecordComponentElement#getAccessor

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
To reproduce on Java 15:

1. git clone https://github.com/filiphr/mapstruct-2294.git
2. Make sure that you have setup Java 15
3. Run: export MAVEN_OPTS="--enable-preview" && ./mvnw clean verify

To reproduce on Java 16.ea.28:

1. git clone https://github.com/filiphr/mapstruct-2294.git
2. Make sure that you have setup Java 15
3. Run: export MAVEN_OPTS="--enable-preview" && ./mvnw clean verify -Djava.version=16

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected a successful compilation
ACTUAL -
On Java 15 the result will be a compilation error coming from the TestProcessor (part of the project)
because TypeElement#getRecordComponents does not return any record components for records coming from another jar (not in the compilation round).

The error message will be: "Record element source.SourceInAnotherPackage has no record components"

On Java 16 the result will be a compilation error coming from the TestProcessor (part of the project)
because `RecordComponentElement#getAccessor` returns `null` for records coming from another jar (not in the compilation round).

The error message will be: "Record component data from record element source.SourceInAnotherPackage has no accessor"


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https://github.com/filiphr/mapstruct-2294
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FREQUENCY : always