Fix sanity checks for distinct E factor settings

Reference #13156

Marlin/src/inc/SanityCheck.h

                 sanity_arr_2[] = DEFAULT_MAX_FEEDRATE,
                 sanity_arr_3[] = DEFAULT_MAX_ACCELERATION;
 
-static_assert(COUNT(sanity_arr_1) >= XYZE, "DEFAULT_AXIS_STEPS_PER_UNIT requires 4 (or more) elements.");
+#define _ARR_TEST(N,I) (sanity_arr_##N[MIN(I,COUNT(sanity_arr_##N)-1)] > 0)
+
+static_assert(COUNT(sanity_arr_1) >= XYZE, "DEFAULT_AXIS_STEPS_PER_UNIT requires X, Y, Z and E elements.");
 static_assert(COUNT(sanity_arr_1) <= XYZE_N, "DEFAULT_AXIS_STEPS_PER_UNIT has too many elements. (Did you forget to enable DISTINCT_E_FACTORS?)");
-static_assert(sanity_arr_1[0] > 0 && sanity_arr_1[1] > 0 && sanity_arr_1[2] > 0
-  && (XYZE_N <= 3 || sanity_arr_1[3] > 0) && (XYZE_N <= 4 || sanity_arr_1[4] > 0)
-  && (XYZE_N <= 5 || sanity_arr_1[5] > 0) && (XYZE_N <= 6 || sanity_arr_1[6] > 0)
-  && (XYZE_N <= 7 || sanity_arr_1[7] > 0) && (XYZE_N <= 8 || sanity_arr_1[8] > 0),
-  "DEFAULT_AXIS_STEPS_PER_UNIT values must be positive.");
+static_assert(   _ARR_TEST(1,0) && _ARR_TEST(1,1) && _ARR_TEST(1,2)
+              && _ARR_TEST(1,3) && _ARR_TEST(1,4) && _ARR_TEST(1,5)
+              && _ARR_TEST(1,6) && _ARR_TEST(1,7) && _ARR_TEST(1,8),
+              "DEFAULT_AXIS_STEPS_PER_UNIT values must be positive.");
 
-static_assert(COUNT(sanity_arr_2) >= XYZE, "DEFAULT_MAX_FEEDRATE requires 4 (or more) elements.");
+static_assert(COUNT(sanity_arr_2) >= XYZE, "DEFAULT_MAX_FEEDRATE requires X, Y, Z and E elements.");
 static_assert(COUNT(sanity_arr_2) <= XYZE_N, "DEFAULT_MAX_FEEDRATE has too many elements. (Did you forget to enable DISTINCT_E_FACTORS?)");
-static_assert(sanity_arr_2[0] > 0 && sanity_arr_2[1] > 0 && sanity_arr_2[2] > 0
-  && (XYZE_N <= 3 || sanity_arr_2[3] > 0) && (XYZE_N <= 4 || sanity_arr_2[4] > 0)
-  && (XYZE_N <= 5 || sanity_arr_2[5] > 0) && (XYZE_N <= 6 || sanity_arr_2[6] > 0)
-  && (XYZE_N <= 7 || sanity_arr_2[7] > 0) && (XYZE_N <= 8 || sanity_arr_2[8] > 0),
-  "DEFAULT_MAX_FEEDRATE values must be positive.");
+static_assert(   _ARR_TEST(2,0) && _ARR_TEST(2,1) && _ARR_TEST(2,2)
+              && _ARR_TEST(2,3) && _ARR_TEST(2,4) && _ARR_TEST(2,5)
+              && _ARR_TEST(2,6) && _ARR_TEST(2,7) && _ARR_TEST(2,8),
+              "DEFAULT_MAX_FEEDRATE values must be positive.");
 
-static_assert(COUNT(sanity_arr_3) >= XYZE, "DEFAULT_MAX_ACCELERATION requires 4 (or more) elements.");
+static_assert(COUNT(sanity_arr_3) >= XYZE, "DEFAULT_MAX_ACCELERATION requires X, Y, Z and E elements.");
 static_assert(COUNT(sanity_arr_3) <= XYZE_N, "DEFAULT_MAX_ACCELERATION has too many elements. (Did you forget to enable DISTINCT_E_FACTORS?)");
-static_assert(sanity_arr_3[0] > 0 && sanity_arr_3[1] > 0 && sanity_arr_3[2] > 0
-  && (XYZE_N <= 3 || sanity_arr_3[3] > 0) && (XYZE_N <= 4 || sanity_arr_3[4] > 0)
-  && (XYZE_N <= 5 || sanity_arr_3[5] > 0) && (XYZE_N <= 6 || sanity_arr_3[6] > 0)
-  && (XYZE_N <= 7 || sanity_arr_3[7] > 0) && (XYZE_N <= 8 || sanity_arr_3[8] > 0),
-  "DEFAULT_MAX_ACCELERATION values must be positive.");
+static_assert(   _ARR_TEST(3,0) && _ARR_TEST(3,1) && _ARR_TEST(3,2)
+              && _ARR_TEST(3,3) && _ARR_TEST(3,4) && _ARR_TEST(3,5)
+              && _ARR_TEST(3,6) && _ARR_TEST(3,7) && _ARR_TEST(3,8),
+              "DEFAULT_MAX_ACCELERATION values must be positive.");
+
+#undef _ARR_TEST
 
 #if ENABLED(CNC_COORDINATE_SYSTEMS) && ENABLED(NO_WORKSPACE_OFFSETS)
   #error "CNC_COORDINATE_SYSTEMS is incompatible with NO_WORKSPACE_OFFSETS."