Enable via yul or explain why disabled.

test/libsolidity/SolidityEndToEndTest.cpp

@@ -1381,6 +1381,8 @@ BOOST_AUTO_TEST_CASE(internal_constructor)
 			constructor() {}
 		}
 	)";
+	// via yul disabled because it will throw an error instead of
+	// returning empty bytecode.
 	BOOST_CHECK(compileAndRunWithoutCheck({{"", sourceCode}}, 0, "C").empty());
 }
 

test/libsolidity/semanticTests/array/copying/dirty_memory_bytes_to_storage_copy.sol

@@ -6,6 +6,7 @@ contract C {
             mstore(m, 8)
             mstore(add(m, 32), "deadbeef15dead")
         }
+        // via yul disabled because this truncates the string.
         x = m;
         assembly {
             r := sload(x.slot)

test/libsolidity/semanticTests/calldata/calldata_array_dynamic_bytes.sol

@@ -63,8 +63,7 @@ contract C {
     }
 }
 
-// found expectation comments:
+// via yul disabled because of stack issues.
-// same offset for both arrays @ ABI_CHECK(
 
 // ====
 // compileViaYul: false

test/libsolidity/semanticTests/modifiers/function_modifier_loop.sol

@@ -8,6 +8,11 @@ contract C {
         r += 1;
     }
 }
+// via yul disabled because the return variables are
+// fresh variables each time, while in the old code generator,
+// they share a stack slot when the function is
+// invoked multiple times via `_`.
+
 // ====
 // compileViaYul: false
 // ----

test/libsolidity/semanticTests/modifiers/function_modifier_multi_invocation.sol

@@ -8,6 +8,11 @@ contract C {
         r += 1;
     }
 }
+// via yul disabled because the return variables are
+// fresh variables each time, while in the old code generator,
+// they share a stack slot when the function is
+// invoked multiple times via `_`.
+
 // ====
 // compileViaYul: false
 // ----

test/libsolidity/semanticTests/modifiers/function_modifier_multi_with_return.sol

@@ -11,6 +11,11 @@ contract C {
         return r;
     }
 }
+// via yul disabled because the return variables are
+// fresh variables each time, while in the old code generator,
+// they share a stack slot when the function is
+// invoked multiple times via `_`.
+
 // ====
 // compileViaYul: false
 // ----

test/libsolidity/semanticTests/various/negative_stack_height.sol

@@ -58,6 +58,9 @@ contract C {
         )
     {}
 }
+
+// via yul disabled because of stack issues.
+
 // ====
 // compileViaYul: false
 // ----