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

Description

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.

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