Revert "Add Steve Johnson-style parser recovery rules:"

This reverts commit 97f8ee0d1b.

test/libsolidity/errorRecoveryTests/constructor_recovers.sol

@@ -1,20 +0,0 @@
-pragma solidity >=0.0.0;
-
-contract Error1 {
-  constructor() public {
-    balances[tx.origin] = ; // missing RHS.
-  }
-
-  // Without error recovery we stop due to the above error.
-  // Error recovery however recovers at the above ';'
-  // There should be an AST for the above, albeit with error
-  // nodes.
-
-  // This function parses properly and should give AST info.
-  function five() public view returns(uint) {
-    return 5;
-  }
-}
-// ----
-// ParserError: (95-96): Expected primary expression.
-// Warning: (95-96): Recovered in Statement at ';'.