Summary

• Generate %makearray_dynamic tests (131a2cf) (see below)
• Move %makearray_dynamic_uninit to layouts_beta (from layouts_alpha) (b719e45)
• Use the existing gen_product_array_helpers.ml infra to test %makearay_dynamic_uninit(4ce5167) and unboxed float arrays
  (9c07d0f)
• Test that %makearray_dynamic_uninit only accepts GC-ignored layouts (3e16c1c)

Generated tests

We generate tests for uninitialized/initialized heap/local arrays of various types and sizes. For each such array, we do the following.

1. Create an array
2. For initialized arrays, check all elements have the correct value
3. Fill array with distinct values and read back those values
4. Check that getting bad indices errors
5. Check that setting bad indices errors
6. Check that array contents were unaffected by setting bad indices
7. Overlapping blits
8. Blits to heap arrays
9. Blits to local arrays

We only perform steps 7-9 for arrays whose elements are GC-ignorable. This can be changed once blits work for all arrays.

The tests are generated by testsuite/tests/typing-layouts-arrays/generate_makearray_dynamic_tests.ml. This generates testsuite/tests/typing-layouts-arrays/generated_test.ml. This test caught the bug fixed by 8651275 (minimal example).

The test generator is loosely based on testsuite/tests/mixed-blocks/generate_mixed_blocks_code.ml.