Spring Get class names via Class object

I was getting java.lang.NoClassDefFoundError on org/springframework/expression/spel/CompiledExpression after ProGuard shrinking. This alleviates issues finding those classes.

Comment From: sbrannen

Hi @BFergerson,

Thanks for the PR.

Unfortunately, the proposed change results in 80 failed tests.

The fully qualified class names are required in order for them to be loaded via org.springframework.expression.spel.standard.SpelCompiler.createExpressionClass(SpelNodeImpl).

In light of that, I am declining this PR.