🐛[Bug]: internal/storage/memory/memory_test

[sixcolors]

A problem was just noticed in internal/storage/memory/memory_test.go where var testStore = new is set globally in the package, and I got memory corruption issues, that randomly occurred. Since this pkg is using sync and a mutex, we should probably investigate the cause.

--- FAIL: Test_Storage_Memory_Delete (0.00s)
    memory_test.go:98: 
                Error Trace:    /Users/sixcolors/Documents/GitHub/fiber/internal/storage/memory/memory_test.go:98
                Error:          Should be empty, but was [100 111 101]
                Test:           Test_Storage_Memory_Delete
FAIL

Originally posted by @sixcolors in #2871 (comment)

[gaby]

@sixcolors This is fixed by #2892

[gaby]

Fixed via #2892