Tests: Add testcase for problematic ABC DONE check

tests/techmap/bug5495.abc

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+
+fraig_store; fraig_restore

tests/techmap/bug5495.sh

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+#!/usr/bin/env bash
+
+if ! timeout 5 ../../yosys bug5495.v -p 'hierarchy; techmap; abc -script bug5495.abc' ; then
+    echo "Yosys failed to complete"
+    exit 1
+fi
+

tests/techmap/bug5495.v

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+module simple(I1, I2, O);
+	input wire I1;
+	input wire I2;
+	output wire O;
+
+	assign O = I1 | I2;
+endmodule