COMPMID-2486: Remove/add disabled compiler warnings

Removed the following flags:
-Wno-vla
-Wno-strict-overflow

Added:
-Wformat-security

Change-Id: I49eb3d724e14db796e543164295674617c37cb65
Signed-off-by: Michalis Spyrou <michalis.spyrou@arm.com>
Reviewed-on: https://review.mlplatform.org/c/2109
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Michele Di Giorgio <michele.digiorgio@arm.com>
diff --git a/tests/AssetsLibrary.h b/tests/AssetsLibrary.h
index a512dab..f535f16 100644
--- a/tests/AssetsLibrary.h
+++ b/tests/AssetsLibrary.h
@@ -491,12 +491,12 @@
 void AssetsLibrary::fill_boxes(T &&tensor, D &&distribution, std::random_device::result_type seed_offset) const
 {
     using ResultType = typename std::remove_reference<D>::type::result_type;
-    std::mt19937 gen(_seed + seed_offset);
-    TensorShape  shape(tensor.shape());
-    const int    num_boxes = tensor.num_elements() / 4;
+    std::mt19937   gen(_seed + seed_offset);
+    TensorShape    shape(tensor.shape());
+    const uint32_t num_boxes = tensor.num_elements() / 4;
     // Iterate over all elements
     std::uniform_real_distribution<> size_dist(0.f, 1.f);
-    for(int element_idx = 0; element_idx < num_boxes * 4; element_idx += 4)
+    for(uint32_t element_idx = 0; element_idx < num_boxes * 4; element_idx += 4)
     {
         const ResultType delta   = size_dist(gen);
         const ResultType epsilon = size_dist(gen);
@@ -538,7 +538,8 @@
     }
 
     // Iterate over all elements
-    for(int element_idx = 0; element_idx < tensor.num_elements(); ++element_idx)
+    const uint32_t num_elements = tensor.num_elements();
+    for(uint32_t element_idx = 0; element_idx < num_elements; ++element_idx)
     {
         Coordinates id = index2coord(shape, element_idx);