Fix conversion.

test/libsolidity/semanticTests/fixedPoint/conversion_large.sol

@@ -0,0 +1,10 @@
+contract C {
+    function test() public pure returns (uint a) {
+        ufixed256x77 x = 1.0000001234;
+        return uint(x);
+    }
+}
+// ====
+// compileViaYul: also
+// ----
+// test() -> 0