fix: check preconditions before running exploit code for the solidity bounty

tests/bounties/solidity-bounty/start.sh

@@ -1,4 +1,44 @@
 #!/bin/sh
+
+#
+# Validate exploit code - Exploit code file must contain only ascii characters
+#
+grep -q "[^[:print:]]" $1 
+status=$?
+if [ $status -eq 0 ]; then
+    >&2 echo "Invalid exploit code: File contains non-ascii characters"
+    exit 1
+fi
+if [ $status -eq 2 ]; then
+    >&2 echo "Invalid exploit code: Error reading the file"
+    exit 1
+fi
+
+
+#
+# Validate exploit code - No experimental directives are allowed
+#
+grep -q "experimental" $1
+status=$?
+if [ $status -eq 0 ]; then
+    >&2 echo "Invalid exploit code: contains 'experimental' keyword"
+    exit 1
+fi
+
+
+#
+# Validate exploit code - Requires specific version of Solidity
+#
+grep -q "pragma solidity 0.8.26" $1
+status=$?
+if [ $status -eq 1 ]; then
+    >&2 echo "Invalid exploit code: pragma solidity 0.8.26 not found"
+    exit 1
+fi
+
+#
+# Run the exploit code
+#
 ./solc $1
 status=$?
 # Status is always 139 when program crashes with "Segmentation fault" (SIGSEGV)