Correctly handle variables imported or exported by modules. (#3270)

Remove var declaration workarounds and correctly create / use variables for modules.

Still missing: create lexical environment for automatic module conversion.
(Or remove this feature overall.)

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

jerry-core/ecma/base/ecma-globals.h

@@ -105,6 +105,7 @@ typedef enum
   ECMA_PARSE_HAS_IMPL_SUPER = (1u << 4), /**< the current context has implicit parent class */
   ECMA_PARSE_HAS_STATIC_SUPER = (1u << 5), /**< the current context is a static class method */
   ECMA_PARSE_EVAL = (1u << 6), /**< eval is called */
+  ECMA_PARSE_MODULE = (1u << 7), /**< module is parsed */
 } ecma_parse_opts_t;
 
 /**