Add trace call expr to allow trace Tensor data
at the runtime. By default the default handler
is enabled which prints a tracing data to stdout,
otherwise user should specify a call_back as
global_function (aka @tvm.register_func).

The issue is related to:
https://discuss.tvm.ai/t/idea-trace-expression/945

The pass which instruments checkers before
memory accesses (load/store).
This allows to handle invalid memory accesses.

The patch is related to issue:
https://discuss.tvm.ai/t/array-bounds-checking/944

* Implement C code generation with tests

* Code cleanup

* Implement C code generation with tests

* Code cleanup

* tabs to spaces

* make lint compliant

* update export_library and reserve unique C keywords

* move ReserveKeywordsAsUnique to codegen_c

* some documentation and code cleanup

* use tvm.contrib.util for tempdir in testcases

* [TOPI] add nn schedulers for HLS backends

* fix pylint

* fix topi transform test

* [CODEGEN][AOCL] Add math intrinsic rules

* introduce aocl_emu target for AOCL emulation

* rename aocl_emu with aocl_sw_emu

* update docs

* Use int for int8x4 due to performance overhead of char4

* Add a comment about using int

* Remove invalid test

* [TOPI] add injective scheduler for HLS backends

* Introduced PrintBinaryExpr