Add maxBytesLocalDisk support for Ehcache 2

[Copilot]

setMaxBytesLocalDisk was missing from the Ehcache 2 adapter, making it impossible to enforce a disk-size ceiling on MyBatis caches.

Changes

• AbstractEhcacheCache — adds setMaxBytesLocalDisk(long) and a protected rebuildCacheWith(CacheConfiguration) template method. Ehcache 2 enforces mutual exclusivity between maxBytesLocalDisk and maxEntriesLocalDisk, and prohibits switching disk pool types on a live cache instance; the setter works around this by constructing a fresh CacheConfiguration (preserving TTI/TTL/heap/eviction-policy) and replacing the running cache via the CacheManager.

• EhBlockingCache — overrides rebuildCacheWith to re-apply the BlockingCache decorator after the underlying cache is replaced.

• EhcacheTest — adds shouldSetMaxBytesLocalDisk verifying the byte limit is applied, maxEntriesLocalDisk is cleared, and the cache remains operational after the rebuild.

<!-- ehcache.xml or MyBatis mapper cache config -->
<cache type="org.mybatis.caches.ehcache.EhcacheCache">
  <property name="maxBytesLocalDisk" value="10485760"/> <!-- 10 MB -->
</cache>

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[coveralls]

coverage: 74.444% (-2.4%) from 76.812%
when pulling 2fd8449 on copilot/62-fix-issue-ehcache2
into 1bd0e7b on support/ehcache2.