Support break in loop code generation

[KingParmenides]

Fixes #93.

Summary:

• Fold javac if-then-goto loop break bytecode into an if composite before loop folding.
• Track active loop break targets while writing loop bodies and emit break for matching forward gotos.
• Update Break and ForBreak codegen tests to expect generated OpenCL instead of ClassParseException.

Validation:

• mvn -q -Dmaven.repo.local=/private/tmp/aparapi-m2 -DsecondaryCacheDir=/private/tmp/aparapi-zinc-jdk11 -DargLine="-XX:+IgnoreUnrecognizedVMOptions" -Dtest=BreakTest,ForBreakTest,ContinueTest,MultiContinueTest test
• mvn -q -Dmaven.repo.local=/private/tmp/aparapi-m2 -DsecondaryCacheDir=/private/tmp/aparapi-zinc-jdk11 -DargLine="-XX:+IgnoreUnrecognizedVMOptions" -Dtest=com.aparapi.codegen.test.*Test,!com.aparapi.codegen.test.If_While_Else_WhileTest test
• mvn -q -Dmaven.repo.local=/private/tmp/aparapi-m2 -DsecondaryCacheDir=/private/tmp/aparapi-zinc-jdk11 -DargLine="-XX:+IgnoreUnrecognizedVMOptions" -DskipTests package
• git diff --check

Note: If_While_Else_WhileTest fails on clean HEAD in this environment with NullPointerException, so I excluded only that known failing class from the broad codegen run.