Simd.js library support

Change description:

1. Implemented support for new SIMD types SIMD.Bool32x4, SIMD.Bool16x8,
SIMD.Bool8x16, SIMD.Int16x8,SIMD.Int8x16, SIMD.Uint32x4, SIMD.Uint16x8,
SIMD.Uint8x16. This adds to the existing types SIMD.Int32x4 and
SIMD.Float32x4 ensuring compatability with the latest SIMDjs specification.

2. Adding new builtin functions for all SIMDJs types to be consistent with the
SIMD.js specification and the polyfill implemntation. This is validated
against the polyfill tests.

3. Updating the syntax and behavior of the existing builtin functions and
removing builtins to be consistent with the SIMD.js specification and the
polyfill.

4. Clean up of existing SIMD unittests to avoid printing SIMD values for
validation. Tests prints only PASS/FAIL while verification and uses
utility methods for comparing the values to the right precision. This
avoids unittest dependency on the printing of numbers.

5. Code refactoring to reduce code size/complexity of the SIMDjs code.

Author: arunetm-zz

lib/Backend/BackEnd.h

@@ -23,27 +23,19 @@
 #include "Language\CodeGenRecyclableData.h"
 #include "Library\JavascriptGenerator.h"
 #include "Library\JavascriptRegularExpression.h"
+#include "Library\StackScriptFunction.h"
+
+#include "Language\InterpreterStackFrame.h"
+#include "Language\ReadOnlyDynamicProfileInfo.h"
 
 #include "Library\StackScriptFunction.h"
 
 #include "Language\InterpreterStackFrame.h"
 #include "Language\ReadOnlyDynamicProfileInfo.h"
 
-// SIMD types
-#include "Library\JavascriptSIMDFloat32x4.h"
-#include "Library\JavascriptSIMDFloat64x2.h"
-#include "Library\JavascriptSIMDInt32x4.h"
-#include "Library\JavascriptSIMDInt8x16.h"
-// SIMD operations
-#include "Language\SIMDFloat32x4Operation.h"
-#include "Language\SIMDFloat64x2Operation.h"
-#include "Language\SIMDInt32x4Operation.h"
-#include "Language\SIMDInt8x16Operation.h"
-// SIMD libs
-#include "Library\SIMDFloat32x4Lib.h"
-#include "Library\SIMDFloat64x2Lib.h"
-#include "Library\SIMDInt32x4Lib.h"
-#include "Library\SIMDInt8x16Lib.h"
+// SIMD_JS
+#include "Library\SimdLib.h"
+#include "Language\SimdOps.h"
 
 // =================
 // Common Includes

lib/Backend/Lower.cpp

@@ -13,6 +13,8 @@
 
 #include "ExternalLowerer.h"
 
+#include "ExternalLowerer.h"
+
 ///----------------------------------------------------------------------------
 ///
 /// Lowerer::Lower