Do not duplicate subassemblies.

Add LinkerObject check and more tests

test/libsolidity/semanticTests/deployedCodeExclusion/subassembly_deduplication.sol

@@ -0,0 +1,42 @@
+contract A {
+    function longdata() pure external returns (bytes memory) {
+        return
+        "xasopca.pngaibngidak.jbtnudak.cAP.BRRSMCPJAGPD KIAJDOMHUKR,SCPID"
+        "xasopca.pngaibngidak.jbtnudak.cAP.BRRSMCPJAGPD KIAJDOMHUKR,SCPID"
+        "M,SEYBDXCNTKIMNJGO;DUIAQBQUEHAKMPGIDSAJCOUKANJBCUEBKNA.GIAKMV.TI"
+        "AJMO<KXBANJCPGUD ABKCJIDHA NKIMAJU,EKAMHSO;PYCAKUM,L.UCA MR;KITA"
+        "M,SEYBDXCNTKIMNJGO;DUIAQBQUEHAKMPGIDSAJCOUKANJBCUEBKNA.GIAKMV.TI"
+        "AJMO<KXBANJCPGUD ABKCJIDHA NKIMAJU,EKAMHSO;PYCAKUM,L.UCA MR;KITA"
+        " .RPOKIDAS,.CKUMT.,ORKAD ,NOKIDHA .CGKIAD OVHAMS CUAOGT DAKN OIT"
+        "xasopca.pngaibngidak.jbtnudak.cAP.BRRSMCPJAGPD KIAJDOMHUKR,SCPID"
+        "M,SEYBDXCNTKIMNJGO;DUIAQBQUEHAKMPGIDSAJCOUKANJBCUEBKNA.GIAKMV.TI"
+        "AJMO<KXBANJCPGUD ABKCJIDHA NKIMAJU,EKAMHSO;PYCAKUM,L.UCA MR;KITA"
+        "apibakrpidbacnidkacjadtnpdkylca.,jda,r.kuadc,jdlkjd',c'dj, ncg d"
+        "anosumantkudkc,djntudkantuadnc,ui,c.ud,.nujdncud,j.rsch'pkl.'pih";
+    }
+}
+
+contract C {
+    constructor() {
+    }
+
+    function a() external returns (bytes memory) {
+        return type(A).creationCode;
+    }
+
+    function b() external returns (A) {
+        return new A();
+    }
+
+    function test() public view returns (bool) {
+        uint x;
+        assembly {
+            x := codesize()
+        }
+        return type(A).creationCode.length < x &&
+            x < 2 * type(A).creationCode.length;
+    }
+}
+
+// ----
+// test() -> true