Adjust tests.

test/libsolidity/semanticTests/abiEncoderV2/struct/mediocre2_struct.sol

@@ -9,6 +9,7 @@ contract C {
     }
 }
 // ====
+// requiresYulOptimizer: minimalStack
 // compileViaYul: also
 // ----
 // f(uint256,(address,uint256[])[2],uint256): 7, 0x60, 8, 0x40, 0xE0, 0x0, 0x40, 2, 0x11, 0x12, 0x99, 0x40, 4, 0x31, 0x32, 0x34, 0x35 -> 7, 0x0, 8

test/libsolidity/semanticTests/abiEncoderV2/struct/mediocre_struct.sol

@@ -9,6 +9,7 @@ contract C {
     }
 }
 // ====
+// requiresYulOptimizer: minimalStack
 // compileViaYul: also
 // ----
 // f(uint256,(address)[2],uint256): 7, 0, 0, 8 -> 7, 0, 8

test/libsolidity/semanticTests/abiEncoderV2/struct/struct_function.sol

@@ -11,6 +11,7 @@ contract C {
     function g() public returns (uint) { return 7; }
 }
 // ====
+// requiresYulOptimizer: minimalStack
 // compileViaYul: also
 // ----
 // test() -> 7, 3

test/libsolidity/semanticTests/abiEncoderV2/struct/struct_simple.sol

@@ -10,6 +10,7 @@ contract C {
     }
 }
 // ====
+// requiresYulOptimizer: minimalStack
 // compileToEwasm: also
 // compileViaYul: also
 // ----