[ref model] Change PadOp's padding to Shape

Changed to use pad input of PadOp for testing.
The pad input is now a tensor of tosa.shape type.

moved padding error checking from checkTensorAttributes to eval
modified pad's PadOutputShapeMismatch test generation to avoid
generating output shapes with dimensions <= 0

Signed-off-by: Tai Ly <tai.ly@arm.com>
Change-Id: I437c86d9a012903458a648667f6693db67b97d76
diff --git a/.gitignore b/.gitignore
index e861e24..941cf20 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,7 +3,7 @@
 
 __pycache__/
 build/
-build-debug/
+debug-build/
 .cache
 compile_commands.json
 dist/