Added positive tests in stake pool and fixed several bugs in instructions (#788)

* Added positive tests for withdraw, claim, set owner, set authority, several bugs fixed

* Fixed PR comments

* Fixed constant with leading zero

* Deposit tests refactoring

Author: ysavchenko

stake-pool/program/src/instruction.rs

@@ -280,9 +280,8 @@ pub fn claim(
     pool_mint: &Pubkey,
     token_program_id: &Pubkey,
     stake_program_id: &Pubkey,
-    amount: u64,
 ) -> Result<Instruction, ProgramError> {
-    let args = StakePoolInstruction::Withdraw(amount);
+    let args = StakePoolInstruction::Claim;
     let data = args.serialize()?;
     let accounts = vec![
         AccountMeta::new(*stake_pool, false),
@@ -338,7 +337,7 @@ pub fn set_owner(
     stake_pool_new_owner: &Pubkey,
     stake_pool_new_fee_receiver: &Pubkey,
 ) -> Result<Instruction, ProgramError> {
-    let args = StakePoolInstruction::SetStakingAuthority;
+    let args = StakePoolInstruction::SetOwner;
     let data = args.serialize()?;
     let accounts = vec![
         AccountMeta::new(*stake_pool, false),