Description:
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Problem:
Two processes race in to create the cross-process, shared memory map for the opcode cache.  During initialization of that memory mapped file, there's an error, that leaves partial information about the memory mapped file in a different chunk of cross-process, shared memory used to figure out where Wincache mapped things (php_wincache!filemap_global_context).  This partial information guarantees that all Wincache instances will attempt to map the opcode cache at different addresses.  The failures may not be instantaneous, since some processes might "accidently" map their opcode cache at the same address as a majority of other instances.
  
Fix:
Detect this failure, and clear out the (now invalid) filemap_global_context entry, so other processes don't accidently use the entry.

Expected result:
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No AV

Actual result:
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AV deref'ing a zend_op_array in an address not mapped to the current process.