Migrate Spock tests to Junit 5 tests and remove groovy from the build.

Rationale:

• The Java driver uses; Junit 4 (api) Junit 5 and Spock tests - this would help simplify the stack towards just being Junit based.
• Using Spock requires Groovy to compile the Java code via gradle. - Slow
• Spock tests use a Spock & Groovy DSL - this requires extra cognative effort to maintain
• Junit5 and Java 8 min support reduces the verboseness of testing which was a core reason for Spock adoption.
• Specification testing now covers much of the the Spock tests - so the amount of tests could be reduced.
• Spock adds the following dependencies to the build:

  +--- org.spockframework:spock-bom:2.1-groovy-3.0
  |    +--- org.spockframework:spock-core:2.1-groovy-3.0 (c)
  |    \--- org.spockframework:spock-junit4:2.1-groovy-3.0 (c)
  +--- org.spockframework:spock-core -> 2.1-groovy-3.0
  |    +--- org.codehaus.groovy:groovy:3.0.9
  |    +--- org.junit.platform:junit-platform-testkit -> 1.14.3
  |    |    +--- org.junit:junit-bom:5.14.3 (*)
  |    |    +--- org.assertj:assertj-core:3.27.3
  |    |    |    \--- net.bytebuddy:byte-buddy:1.15.11
  |    |    +--- org.opentest4j:opentest4j:1.3.0
  |    |    \--- org.junit.platform:junit-platform-launcher:1.14.3 (*)
  |    +--- org.jetbrains:annotations:20.1.0
  |    +--- org.ow2.asm:asm:9.2
  |    +--- net.bytebuddy:byte-buddy:1.12.1 -> 1.15.11
  |    +--- cglib:cglib-nodep:3.3.0
  |    +--- org.objenesis:objenesis:3.2 -> 3.3
  |    +--- org.junit:junit-bom:5.8.1 -> 5.14.3 (*)
  |    +--- org.junit.platform:junit-platform-engine -> 1.14.3 (*)
  |    \--- org.hamcrest:hamcrest:2.2
  +--- org.spockframework:spock-junit4 -> 2.1-groovy-3.0
  |    +--- org.codehaus.groovy:groovy:3.0.9
  |    +--- org.spockframework:spock-core:2.1-groovy-3.0 (*)
  |    \--- junit:junit:4.13.2 (*)
    

• Migrating towards Junit 6 (JAVA-5977) may require this migration