THRIFT-6133: Handle oversized Ruby memory-buffer reads

[kpumuk]

Native MemoryBufferTransport converted read sizes to a signed C integer before checking the bytes available. Positive Compact lengths above INT_MAX therefore raised RangeError instead of reporting truncated input.

The native implementation now preserves the requested Compact length through the availability check and returns EOFError for truncated oversized read and read_all calls, matching pure Ruby behavior.

• Did you create an Apache Jira ticket? (THRIFT-6133)
• If a ticket exists: Does your pull request title follow the pattern "THRIFT-NNNN: describe my issue"?
• Did you squash your changes to a single commit? (not required, but preferred)
• Did you do your best to avoid breaking changes? If one was needed, did you label the Jira ticket with "Breaking-Change"?
• If your change does not involve any code, include [skip ci] anywhere in the commit message to free up build resources.

[kpumuk]

Fuzzer crash:

Running: /mnt/scratch0/clusterfuzz/bot/inputs/fuzzer-testcases/crash-29d1631cf96f7c2f537740ee480968f6459d51bf
--
  | /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:360:in `read_all': integer 3397380576 too big to convert to `int' (RangeError)
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:360:in `read_string'
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:360:in `skip'
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:368:in `skip'
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:368:in `skip'
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:368:in `skip'
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:368:in `skip'
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:368:in `skip'
  | from /mnt/scratch0/clusterfuzz/bot/builds/clusterfuzz-builds_thrift-rb_0e62be81ffe482a27e2d02fba3412b99b470d7a9/revisions/thrift/lib/rb/lib/thrift/protocol/base_protocol.rb:391:in `block in skip'
  | from <internal:numeric>:237:in `times'
 ```