Fix returning directly instantiated arrays

[pnm03]

Fixes #66.

This is intended as a submission for the `$25 bounty on returning directly instantiated arrays.

Summary:

• Allow return new <primitive>[size] by emitting a named local return array before the return statement.
• Match the generated OpenCL shape used by the existing supported workaround: assign the new array to a local variable, then return that local.
• Update the primitive direct-new array codegen tests and their fixture comments.
• Re-enable the runtime regression test that demonstrates the issue.

Validation:

• git diff --check
• mvn '-Dtest=ReturnBooleanNewArrayTest,ReturnByteArrayNewTest,ReturnDoubleArrayNewTest,ReturnFloatArrayNewTest,ReturnIntArrayNewTest,ReturnLongArrayNewTest,ReturnShortArrayNewTest,ReturnInstantiatedArrayDirectlyTest' test