Fix: tde encrypt buffer context don't use share memory

[kongfanshen-0801]

Now we Fix: tde encrypt buffer context don't use share memory

We did not calculate the size of shared memory for BufEncCtx and BufDecCtx in the CreateSharedMemoryAndMemories function, which is a potential issue. There is actually no need to use shared memory here, as the parent process does not read the values of BufEncCtx and BufDecCtx. When we use AES algorithm the BufEncCtx and BufDecCtx also does not use shared memory. In order to maintain a consistent code style,we use malloc. cann't use palloc to apply for memory here, as TopmemoryContext is NULL during initialization and the memoryContext has not been setted yet.

Fixes #ISSUE_Number

What does this PR do?

Type of Change

• [x] Bug fix (non-breaking change)
• [ ] New feature (non-breaking change)
• [ ] Breaking change (fix or feature with breaking changes)
• [ ] Documentation update

Breaking Changes

Test Plan

• [ ] Unit tests added/updated
• [ ] Integration tests added/updated
• [ ] Passed make installcheck
• [ ] Passed make -C src/test installcheck-cbdb-parallel

Impact

Performance:

User-facing changes:

Dependencies:

Checklist

• [ ] Followed contribution guide
• [ ] Added/updated documentation
• [ ] Reviewed code for security implications
• [ ] Requested review from cloudberry committers

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