Added fuzz test attribute

This acts as a marker to indicate a fuzz test. It should reference a
define, usually SEED, that can be randomized to get interesting test
permutations.

This is currently unused, but could lead to some interesting uses such
as time-based fuzz testing. It's also just useful for inspecting the
tests (make test-list).

tests/test_files.toml

@@ -792,6 +792,7 @@ defines.SIZE = [
     '4*BLOCK_SIZE',
 ]
 defines.SEED = 'range(20)'
+fuzz = 'SEED'
 if = '(SIZE*N)/BLOCK_SIZE <= 16'
 code = '''
     lfs_t lfs;
@@ -1154,6 +1155,7 @@ defines.SIZE = [
     '4*BLOCK_SIZE',
 ]
 defines.SEED = 'range(20)'
+fuzz = 'SEED'
 if = '(SIZE*N)/BLOCK_SIZE <= 16'
 code = '''
     lfs_t lfs;
@@ -2270,6 +2272,7 @@ defines.SIZE = [
     '4*BLOCK_SIZE',
 ]
 defines.SEED = 'range(20)'
+fuzz = 'SEED'
 if = '(SIZE*N)/BLOCK_SIZE <= 16'
 code = '''
     lfs_t lfs;
@@ -2466,6 +2469,7 @@ defines.SIZE = [
     '4*BLOCK_SIZE',
 ]
 defines.SEED = 'range(20)'
+fuzz = 'SEED'
 if = '(SIZE*N)/BLOCK_SIZE <= 16'
 code = '''
     lfs_t lfs;
@@ -2686,6 +2690,7 @@ defines.SIZE = [
     '4*BLOCK_SIZE',
 ]
 defines.SEED = 'range(20)'
+fuzz = 'SEED'
 if = '(SIZE*N)/BLOCK_SIZE <= 16'
 reentrant = true
 code = '''