Fix bugs in JodaTime to JavaTime migration recipe

[amishra-u]

What's changed?

Fixed following bugs in JodaTime to JavaTime migration recipe..

1. MethodInvocation Migration: When the select of a MethodInvocation is a MethodCall and the select has not been migrated, the migration template is no longer incorrectly applied to the MethodInvocation.
2. Variable Initializer Handling: Variables declared inside variable initializers of non-joda type were previously skipped by the JodaTimeScanner. Due to which scanner failed to mark unsafe variables in such contexts. Fixed it.

Note: During debugging also found issue with FlowPath Analysis added unit test for the same

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[timtebeek]

Thanks for the continued work here and in rewrite-analysis @amishra-u !