Mangle OpenCL reserved Java identifiers

[OnlyYu1996]

Fixes #54.

This updates OpenCL code generation so Java identifiers that are legal Java names but reserved in OpenCL are emitted with a deterministic __javaReserved suffix instead of being written verbatim.

Covered paths include:

• instance fields and generated This struct members
• kernel arguments and field assignment glue
• method arguments
• local variable declarations, loads, increments, and inline/multi assignment references

Validation run locally on Windows with JDK 8 and Maven 3.6.3:

• mvn -q -Dstyle.color=never -Dtest=OpenCLKeywordIdentifiersTest,AccessIntArrayTest,ByteParamsSimpleTest,AssignAndPassAsParameterTest,ObjectArrayMemberAccessTest test
• mvn -q -Dstyle.color=never -DskipTests test-compile
• mvn -q -Dstyle.color=never -Dtest=com.aparapi.codegen.test.*Test test
• git diff --check