Revert "feat: add support for getGenesisHash RPC (solana-labs#19732)"

This reverts commit 9041ccd.

web3.js/src/connection.ts

@@ -2963,18 +2963,6 @@ export class Connection {
     return res.result;
   }
 
-  /**
-   * Fetch the genesis hash
-   */
-  async getGenesisHash(): Promise<string> {
-    const unsafeRes = await this._rpcRequest('getGenesisHash', []);
-    const res = create(unsafeRes, jsonRpcResult(string()));
-    if ('error' in res) {
-      throw new Error('failed to get genesis hash: ' + res.error.message);
-    }
-    return res.result;
-  }
-
   /**
    * Fetch a processed block from the cluster.
    */

web3.js/test/connection.test.ts

@@ -2668,17 +2668,6 @@ describe('Connection', () => {
     expect(version['solana-core']).to.be.ok;
   });
 
-  it('getGenesisHash', async () => {
-    await mockRpcResponse({
-      method: 'getGenesisHash',
-      params: [],
-      value: 'GH7ome3EiwEr7tu9JuTh2dpYWBJK3z69Xm1ZE3MEE6JC',
-    });
-
-    const genesisHash = await connection.getGenesisHash();
-    expect(genesisHash).not.to.be.empty;
-  });
-
   it('request airdrop', async () => {
     const account = Keypair.generate();