RewriteTest for TempDir and cleanup unused imports & deprecations

[timtebeek]

Based on feedback received in #252 (comment)

JavaRecipeTest is being replaced with RewriteTest

[timtebeek]

No idea where the sudden test failure might be coming from:

JUnitFailToAssertJFailTest > inlineReference() FAILED
    java.lang.AssertionError: Failed to run parse sources or recipe
        at org.openrewrite.RecipeTest$DefaultImpls._get_executionContext_$lambda-0(RecipeTest.kt:36)
        at org.openrewrite.RecipeTest$DefaultImpls$$Lambda$442/0x000000080122db18.accept(Unknown Source)
        at org.openrewrite.RecipeScheduler.lambda$scheduleVisit$5(RecipeScheduler.java:244)
        at org.openrewrite.RecipeScheduler$$Lambda$578/0x0000000801346610.apply(Unknown Source)
        at org.openrewrite.RecipeScheduler.lambda$mapAsync$0(RecipeScheduler.java:49)
        at org.openrewrite.RecipeScheduler$$Lambda$579/0x0000000801346880.call(Unknown Source)
        at org.openrewrite.scheduling.DirectScheduler.schedule(DirectScheduler.java:35)
        at org.openrewrite.RecipeScheduler.mapAsync(RecipeScheduler.java:50)
        at org.openrewrite.RecipeScheduler.scheduleVisit(RecipeScheduler.java:190)
        at org.openrewrite.RecipeTest$RecipeSchedulerCheckingExpectedCycles.scheduleVisit(RecipeTest.kt:218)
        at org.openrewrite.RecipeScheduler.scheduleRun(RecipeScheduler.java:86)
        at org.openrewrite.Recipe.run(Recipe.java:287)
        at org.openrewrite.RecipeTest$DefaultImpls.assertChangedBase(RecipeTest.kt:108)
        at org.openrewrite.RecipeTest$DefaultImpls.assertChangedBase(RecipeTest.kt:57)
        at org.openrewrite.java.JavaRecipeTest$DefaultImpls.assertChanged(JavaRecipeTest.kt:66)
        at org.openrewrite.java.testing.assertj.JUnitFailToAssertJFailTest.assertChanged(JUnitFailToAssertJFailTest.kt:23)
        at org.openrewrite.java.JavaRecipeTest$DefaultImpls.assertChanged$default(JavaRecipeTest.kt:49)
        at org.openrewrite.java.testing.assertj.JUnitFailToAssertJFailTest.inlineReference(JUnitFailToAssertJFailTest.kt:161)

        Caused by:
        org.openrewrite.UncaughtVisitorException: java.lang.IllegalStateException: Unable to construct Java11Parser.
            at app//org.openrewrite.TreeVisitor.visit(TreeVisitor.java:253)
            at app//org.openrewrite.TreeVisitor.visit(TreeVisitor.java:145)
            at app//org.openrewrite.java.JavaTemplate.withTemplate(JavaTemplate.java:520)
            at app//org.openrewrite.java.JavaTemplate.withTemplate(JavaTemplate.java:42)
            at app//org.openrewrite.java.tree.J.withTemplate(J.java:82)
            at app//org.openrewrite.java.testing.assertj.JUnitFailToAssertJFail$JUnitFailToAssertJFailVisitor$UnqualifiedMethodInvocations.visitMethodInvocation(JUnitFailToAssertJFail.java:143)
            at app//org.openrewrite.java.testing.assertj.JUnitFailToAssertJFail$JUnitFailToAssertJFailVisitor$UnqualifiedMethodInvocations.visitMethodInvocation(JUnitFailToAssertJFail.java:122)
            at app//org.openrewrite.java.tree.J$MethodInvocation.acceptJava(J.java:3414)

No relevant changes made, and does not show up locally, although we've seen some more Unable to construct Java11Parser failures in this project lately.