Add repro for issue #6335. (#6730)

Closes #6335.

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [x] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [ ] If my change requires substantial documentation changes, I have
[requested support from the DevRel
team](https://github.com/FuelLabs/devrel-requests/issues/new/choose)
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

test/src/e2e_vm_tests/test_programs/should_pass/test_contracts/issue_6335_repro/Forc.lock

@@ -0,0 +1,13 @@
+[[package]]
+name = "core"
+source = "path+from-root-2A7B279266ACFF97"
+
+[[package]]
+name = "issue_6335_repro"
+source = "member"
+dependencies = ["std"]
+
+[[package]]
+name = "std"
+source = "path+from-root-2A7B279266ACFF97"
+dependencies = ["core"]

test/src/e2e_vm_tests/test_programs/should_pass/test_contracts/issue_6335_repro/Forc.toml

@@ -0,0 +1,9 @@
+[project]
+authors = ["Fuel Labs <[email protected]>"]
+entry = "main.sw"
+implicit-std = false
+license = "Apache-2.0"
+name = "issue_6335_repro"
+
+[dependencies]
+std = { path = "../../../../reduced_std_libs/sway-lib-std-conversions" }

test/src/e2e_vm_tests/test_programs/should_pass/test_contracts/issue_6335_repro/src/main.sw

@@ -0,0 +1,25 @@
+contract;
+
+use std::bytes::*;
+
+abi MyAbi {
+    fn test() -> u64;
+}
+
+abi FakeAbi {
+    fn test() -> Bytes;
+}
+
+impl MyAbi for Contract {
+    fn test() -> u64 {
+        64
+    }
+}
+
+#[test]
+fn test() {
+    let caller = abi(FakeAbi, CONTRACT_ID);
+    let res  = caller.test();
+    assert(res.len() == 64);
+    let s: str[30] = abi_decode(res.as_raw_slice());
+}

test/src/e2e_vm_tests/test_programs/should_pass/test_contracts/issue_6335_repro/test.toml

@@ -0,0 +1,4 @@
+category = "compile"
+validate_abi = false
+validate_storage_slots = false
+expected_warnings = 0