chore: make compiler happy when optimizer is off

Somehow if we adding 'require' inside 'buildParams' in BondSize and use that in our Routers during their constructor, the compile would
fail with the exception of "Assembly exception for bytecode". However, this would be fine if the optimizer is turned on.

After a few tries, by making it being called in a non-constructor solves the compile issue. Thus, this commit changes the constructor for Routers
to become a 'init' function instead.

This was found because solidity coverage would force turning off the optimizer, see: sc-forks/solidity-coverage#417

plasma_framework/contracts/mocks/exits/payment/routers/PaymentInFlightExitRouterMock.sol

@@ -21,20 +21,20 @@ contract PaymentInFlightExitRouterMock is PaymentInFlightExitRouter {
         SpendingConditionRegistry spendingConditionRegistry,
         IStateTransitionVerifier stateTransitionVerifier,
         ITxFinalizationVerifier txFinalizationVerifier,
-        uint256 supportedTxType
+        uint256 supportTxType
     )
         public
-        PaymentInFlightExitRouter(
+    {
+        PaymentInFlightExitRouter.init(
             plasmaFramework,
             ethVault,
             erc20Vault,
             outputGuardHandlerRegistry,
             spendingConditionRegistry,
             stateTransitionVerifier,
             txFinalizationVerifier,
-            supportedTxType
-        )
-    {
+            supportTxType
+        );
         framework = plasmaFramework;
     }
 

plasma_framework/contracts/mocks/exits/payment/routers/PaymentStandardExitRouterMock.sol

@@ -18,15 +18,15 @@ contract PaymentStandardExitRouterMock is PaymentStandardExitRouter {
         ITxFinalizationVerifier txFinalizationVerifier
     )
         public
-        PaymentStandardExitRouter(
+    {
+        PaymentStandardExitRouter.init(
             plasmaFramework,
             ethVault,
             erc20Vault,
             outputGuardHandlerRegistry,
             spendingConditionRegistry,
             txFinalizationVerifier
-        )
-    {
+        );
         framework = plasmaFramework;
     }
 

plasma_framework/contracts/mocks/utils/BitsWrapper.sol

@@ -20,4 +20,4 @@ contract BitsWrapper {
     {
         return Bits.bitSet(_self, _index);
     }
-}
+}

plasma_framework/contracts/src/exits/payment/PaymentExitGame.sol

@@ -30,15 +30,16 @@ contract PaymentExitGame is IExitProcessor, PaymentStandardExitRouter, PaymentIn
         uint256 supportTxType
     )
         public
-        PaymentStandardExitRouter(
+    {
+        PaymentStandardExitRouter.init(
             framework,
             ethVault,
             erc20Vault,
             outputGuardHandlerRegistry,
             spendingConditionRegistry,
             txFinalizationVerifier
-        )
-        PaymentInFlightExitRouter(
+        );
+        PaymentInFlightExitRouter.init(
             framework,
             ethVault,
             erc20Vault,
@@ -47,8 +48,7 @@ contract PaymentExitGame is IExitProcessor, PaymentStandardExitRouter, PaymentIn
             stateTransitionVerifier,
             txFinalizationVerifier,
             supportTxType
-        )
-    {
+        );
         plasmaFramework = framework;
     }
 

plasma_framework/contracts/src/exits/payment/routers/PaymentInFlightExitRouter.sol

@@ -51,7 +51,7 @@ contract PaymentInFlightExitRouter is IExitProcessor, Operated, OnlyWithValue {
     event IFEBondUpdated(uint128 bondSize);
     event PiggybackBondUpdated(uint128 bondSize);
 
-    constructor(
+    function init(
         PlasmaFramework framework,
         EthVault ethVault,
         Erc20Vault erc20Vault,
@@ -105,6 +105,7 @@ contract PaymentInFlightExitRouter is IExitProcessor, Operated, OnlyWithValue {
             ethVault: ethVault,
             erc20Vault: erc20Vault
         });
+
         startIFEBond = BondSize.buildParams(INITIAL_IFE_BOND_SIZE, BOND_LOWER_BOUND_DIVISOR, BOND_UPPER_BOUND_MULTIPLIER);
         piggybackBond = BondSize.buildParams(INITIAL_PB_BOND_SIZE, BOND_LOWER_BOUND_DIVISOR, BOND_UPPER_BOUND_MULTIPLIER);
     }

plasma_framework/contracts/src/exits/payment/routers/PaymentStandardExitRouter.sol

@@ -42,7 +42,7 @@ contract PaymentStandardExitRouter is
 
     event StandardExitBondUpdated(uint128 bondSize);
 
-    constructor(
+    function init(
         PlasmaFramework framework,
         EthVault ethVault,
         Erc20Vault erc20Vault,

plasma_framework/contracts/src/exits/utils/BondSize.sol

@@ -31,12 +31,13 @@ library BondSize {
         pure
         returns (Params memory)
     {
-        require(initialBondSize > 0, "initialBondSize cannot be 0");
-        require(lowerBoundDivisor > 0, "lowerBoundDivisor cannot be 0");
-        require(upperBoundMultiplier > 0, "upperBoundMultiplier cannot be 0");
-
         // Set the initial value to far in the future
         uint128 initialEffectiveUpdateTime = 2 ** 63;
+
+        require(initialBondSize != 0, "initialBondSize cannot be 0");
+        require(lowerBoundDivisor != 0, "lowerBoundDivisor cannot be 0");
+        require(upperBoundMultiplier != 0, "upperBoundMultiplier cannot be 0");
+
         return Params({
             previousBondSize: initialBondSize,
             updatedBondSize: 0,