Fix unused parameter related build issues on Windows (#3003)

MSVC doen't support __attribute__((unused)),
we should use JERRY_UNUSED macro instead.

Additionally removed the internal jrt.h include from
tests/unit-core/test-common.h which was layering violation.
It made JERRY_ASSERT unavailable, we should use TEST_ASSERT.

JerryScript-DCO-1.0-Signed-off-by: Csaba Osztrogonác oszi@inf.u-szeged.hu

tests/unit-ext/test-common.h

@@ -20,6 +20,8 @@
 
 #define ARRAY_SIZE(array) ((unsigned long) (sizeof (array) / sizeof ((array)[0])))
 
+#define JERRY_UNUSED(x) ((void) (x))
+
 #define TEST_ASSERT(x) \
   do \
   { \