8K level: rank 6 tests support using generator groups

Split generation of conformance tests into groups to avoid a change
in existing tests selection
* A standard group is used for the normal/default conformance tests
* An 8k level group covers the extension of testing for 8k level
* Other arbitrary groups can be created and the group names will be
used to tag the tests, so that in the future they could be filtered

Group selection criteria is in a new dictionary
* A default selection config is used for generation groups
* But a different config can be used for a particular generation group

Added parameter sparsity for pad of rank6 and above, and further
parameter sparsity options to test_select to limit number of tests
selected.

Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: Ib9f1185c0ae6d0957df2116411c17e958157c6d3
diff --git a/verif/generator/tosa_test_gen.py b/verif/generator/tosa_test_gen.py
index 779f59e..c816c6b 100644
--- a/verif/generator/tosa_test_gen.py
+++ b/verif/generator/tosa_test_gen.py
@@ -25,6 +25,7 @@
 
 class TosaTestGen:
     # Maximum rank of tensor supported by test generator.
+    # This currently matches the 8K level defined in the specification.
     TOSA_TENSOR_MAX_RANK = 6
 
     def __init__(self, args):
@@ -3647,7 +3648,6 @@
         "pad": {
             "op": Op.PAD,
             "operands": (1, 0),
-            "rank": (1, 5),
             "build_fcn": (
                 build_pad,
                 TosaTensorGen.tgBasic,