add NDEBUG macro when compile pegasus in release mode

now we use lots of assert() in our code, and do not add NDEBUG macro even when compile in release mode.

to improve:
* add NDEBUG macro when compile pegasus in release mode
* change necessary assert() to dassert()
* test and compare performance with NDEBUG and without NDEBUG

No files or tests are named. Start by locating the release-mode build configuration and the current assert()/dassert() definitions and usages; done means release builds define NDEBUG, necessary assertions use dassert(), and performance is compared with NDEBUG enabled and disabled.

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