interp: limit max instructions per function

compileopts/options.go

@@ -33,6 +33,7 @@ type Options struct {
 	Work            bool // -work flag to print temporary build directory
 	InterpTimeout   time.Duration
 	InterpMaxDepth  int
+	InterpMaxInstr  int
 	PrintIR         bool
 	DumpSSA         bool
 	VerifyIR        bool