Verify the tests for Internal Malloc implementation free all the heap

 Make it more clear that each test of the internal heap implementation
  should free in LIFO order. Without this check, memory can be stranded
  but still pass.

extras/fixture/test/unity_fixture_Test.c

@@ -479,6 +479,10 @@ TEST(LeakDetection, PointerSettingMax)
 //------------------------------------------------------------
 
 TEST_GROUP(InternalMalloc);
+#define TEST_ASSERT_MEMORY_ALL_FREE_LIFO_ORDER(first_mem_ptr, ptr) \
+    ptr = malloc(10); free(ptr);                                   \
+    TEST_ASSERT_EQUAL_PTR_MESSAGE(first_mem_ptr, ptr, "Memory was stranded, free in LIFO order");
+
 
 TEST_SETUP(InternalMalloc) { }
 TEST_TEAR_DOWN(InternalMalloc) { }
@@ -491,6 +495,7 @@ TEST(InternalMalloc, MallocPastBufferFails)
     free(m);
     TEST_ASSERT_NOT_NULL(m);
     TEST_ASSERT_NULL(n);
+    TEST_ASSERT_MEMORY_ALL_FREE_LIFO_ORDER(m, n);
 #endif
 }
 
@@ -502,6 +507,7 @@ TEST(InternalMalloc, CallocPastBufferFails)
     free(m);
     TEST_ASSERT_NOT_NULL(m);
     TEST_ASSERT_NULL(n);
+    TEST_ASSERT_MEMORY_ALL_FREE_LIFO_ORDER(m, n);
 #endif
 }
 
@@ -513,6 +519,7 @@ TEST(InternalMalloc, MallocThenReallocGrowsMemoryInPlace)
     free(n);
     TEST_ASSERT_NOT_NULL(m);
     TEST_ASSERT_EQUAL(m, n);
+    TEST_ASSERT_MEMORY_ALL_FREE_LIFO_ORDER(m, n);
 #endif
 }
 
@@ -523,6 +530,7 @@ TEST(InternalMalloc, ReallocFailDoesNotFreeMem)
     void* n1 = malloc(10);
     void* out_of_mem = realloc(n1, UNITY_INTERNAL_HEAP_SIZE_BYTES/2 + 1);
     void* n2 = malloc(10);
+
     free(n2);
     if (out_of_mem == NULL) free(n1);
     free(m);
@@ -530,5 +538,6 @@ TEST(InternalMalloc, ReallocFailDoesNotFreeMem)
     TEST_ASSERT_NOT_NULL(m);       // Got a real memory location
     TEST_ASSERT_NULL(out_of_mem);  // The realloc should have failed
     TEST_ASSERT_NOT_EQUAL(n2, n1); // If n1 != n2 then realloc did not free n1
+    TEST_ASSERT_MEMORY_ALL_FREE_LIFO_ORDER(m, n2);
 #endif
 }