Fix MacOS enum conversion build errors

[mikee47]

CI is getting errors because code relies on intrinsic conversion of enum to int. This is broken MacOS so this PR suppresses such warnings. Example:

jerryscript/jerry-core/api/jerryscript.c:86:56:
error: arithmetic between different enumeration types ('jerry_binary_operation_t' and 'number_arithmetic_op')
[-Werror,-Wenum-enum-conversion]
   86 | JERRY_STATIC_ASSERT (((NUMBER_ARITHMETIC_SUBTRACTION + ECMA_NUMBER_ARITHMETIC_OP_API_OFFSET) == JERRY_BIN_OP_SUB)
      |                                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[slaff]

Thank you @mikee47