* Updated ICV packages and IPP integration

* core(test): minMaxIdx IPP regression test

* core(ipp): workaround minMaxIdx problem

* core(ipp): workaround meanStdDev() CV_32FC3 buffer overrun

* Returned semicolon after CV_INSTRUMENT_REGION_IPP()

* js: update build script

- support emscipten 1.38.12 (wasm is ON by default)
- verbose build messages

* js: use builtin Math functions

* js: disable tracing code completelly

  - redefine 16-bit multiply operator to perform saturating multiply
    instead of non-saturating multiply
  - implement 8-bit multiply operator to perform saturating multiply
  - implement v_mul_wrap() for 8-bit, 16-bit non-saturating multiply
  - improve performance of v_mul_hi() for VSX
  - update intrin tests with new changes
  - replace unv 16-bit multiplication operator with v_mul_wrap due behavior changes

  - Several improvements depend on vpisarev review

    * initial forward declarations for universal intrinsics
    * move emulating SSE intrinsics into separate file
    * implement v_mul_expand for 8-bit
    * reimplement saturating multiply using v_mul_expand + v_pack
    * map v_expand, v_load_expand, v_load_expand_q to sse4.1
    * fix overflow avx2::v_pack(uint32)
    * implement two universal intrinsics v_expand_low and v_expand_high

_tzcnt_u32() is not exported by clang-cl intrin.h so check for
clang-cl and enable an alterate for _tzcnt_u32()

Some discussions:
http://lists.llvm.org/pipermail/cfe-dev/2016-October/051329.html
https://bugs.llvm.org/show_bug.cgi?id=30506

TEST=Build with clang-cl

to avoid build break without `__OPENCV_BUILD`

Fixes for instrumentation of IPP and OCL (#12637)

* fixed warning about re-declaring variable when both IPP and instrumentation are enabled

* fixed segfault when no funName provided

* compilation fixed when both OCL and instrumentation are enabled

* Remove isIntel check from deep learning layers

* Remove fp16->fp32 fallbacks where it's not necessary

* Fix Kernel::run to prevent localsize > globalsize

* may be an typo fix

* remove identical branch,may be paste error

* add parentheses around macro parameter

* simplify if condition

* check malloc fail

* change the condition of branch removed by commit 3041502861318c85d901e8c08226ff67898c77ed

* rewrote Mat::convertTo() and convertScaleAbs() to wide universal intrinsics; added always-available and SIMD-optimized FP16<=>FP32 conversion

* fixed compile warnings

* fix some more compile errors

* slightly relaxed accuracy threshold for int->float conversion (since we now do it using single-precision arithmetics, not double-precision)

* fixed compile errors on iOS, Android and in the baseline C++ version (intrin_cpp.hpp)

* trying to fix ARM-neon builds

* trying to fix ARM-neon builds

* trying to fix ARM-neon builds

* trying to fix ARM-neon builds

* trying to fix the custom AVX2 builder test failures (false alarms)

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* seemingly disabled false alarm warning in surf.cpp; increased tolerance thresholds in the tests for SolvePnP and in DNN/ENet

POD structures can't have constructors.

Commits:
- 09837928
- 10fb88d0

Excluded changes with std::atomic (C++98 requirement)

- support passing of `std::vector<KeyPoint>` via InputArray

* Bit-exact GaussianBlur reworked to use wide intrinsics

* Added v_mul_hi universal intrinsic

* Removed custom SSE2 branch from bit-exact GaussianBlur

* Removed loop unrolling for gaussianBlur horizontal smoothing

except header file with conversion routines (will be removed in OpenCV 4.0)

Intrinsics must be effective, so don't declare FP16 type/operations if there is no native support.

- CV_FP16: supports load/store into/from float32
- CV_SIMD_FP16: declares FP16 types and native FP16 operations

Multi-argument CV_Assert() is accessible via CV_Assert_N() (with malformed messages).

OpenCV 3.4.3

remove from DNN module headers

All vx_call() must be wrapped into own simd128/simd256/simd512 namespace

```
namespace CV__SIMD_NAMESPACE {
... vx_call declaration is here ...
}
```

Fix for SSE2 intrinsics problem in the part of saturation arithmetic processing during 32s->16u packed conversion -
for some big negative values less than -INT_MAX+32767 the sign of the numbers is lost due to overflow that leads to
incorrect saturation to MAX value, instead of zero.
The issue is not reproduced with CV_ENABLED_INTRINSICS=OFF