Join does not always respect the order of provided parameters (#3511)

[willyborn]

Arrays were be joined in the order the JIT engine generated the arrays iso the order of the parameters.

Description

1. A wrong assumption was made that the JIT engine would generate the arrays in the same order as provided by the parameters. This assumption is violated when one of the generated arrays is an intermediate result of a previous specified JIT generated array. Example of error condition:

af::array A{af::constant(1.,10)};
af::array R{af::join(0,-A,A)};  --> generated af::join(0,A,-A) because A is an intermediate result of -A.

In this fix, the order of the parameters is imposed, independent from the order of JIT generation. PS: This bug appears in OPENCL and CUDA.

2. The same 'unique' identifier "funcName" was generated for JIT kernels, with outputs as only difference. As result, a different kernel could be executed than intended, dependent on the order of the JIT kernel generation.

Additional information about the PR answering following questions:

• bug fix
• can be back ported
• extra test is added covering a large set of possible combinations of similar outputs (567 combinations)

Fixes: #3511

Changes to Users

None

Checklist

• [x] Rebased on latest master
• [x] Code compiles
• [x] Tests pass
• [ ] Functions added to unified API
• [ ] Functions documented

[willyborn]

Do not merge yet. I discovered a new combination giving unexpected results. The testing case will be expended to include more logical combinations (JIT nodes, Block nodes, repeating, dependencies, ...) You will get an updated PR in the coming days.

[willyborn]

Code is updated and join tests are expanded with the generation of multiple join combinations.

For some joins, the kernel of a previous join could be used since both generated the same 'unique' funcName (while having a different kernel) resulting in the reuse of the previously cached kernel iso generating the new one. The chance of happening this is very rare, explaining why I added a systematic combination generator to the tests.

[umar456]

Updated the getFuncName parameters in oneapi.