Revert "[Reland] Implement test cases for blink::VectorMath functions"

This reverts commit 2ec883ba.

Reason for revert: VectorMathTest.Vsma and VectorMathTest.Zvmul
 are failing on Mac. See https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac10.11%20%28retina%29/builds/19138/steps/blink_platform_unittests for detail.

Original change's description:
> [Reland] Implement test cases for blink::VectorMath functions
> 
> Original CL: https://chromium-review.googlesource.com/737877
> 
> This CL avoids erroneous array bound checks in the standard algorithm
> library.
> 
> This is a preparation for AVX optimization of blink::VectorMath
> functions.
> 
> Bug: 778262
> Change-Id: Ifc8465644a048cd0815c993dd824bdf62d04415a
> Reviewed-on: https://chromium-review.googlesource.com/744005
> Reviewed-by: Raymond Toy <rtoy@chromium.org>
> Reviewed-by: Kenneth Russell <kbr@chromium.org>
> Commit-Queue: Eero Häkkinen <eero.hakkinen@intel.com>
> Cr-Commit-Position: refs/heads/master@{#512674}

TBR=kbr@chromium.org,rtoy@chromium.org,eero.hakkinen@intel.com

Change-Id: Ife91931cd9b3f309bd75eeb0ba6525a013f67817
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 778262
Reviewed-on: https://chromium-review.googlesource.com/745921Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Makoto Shimazu <shimazu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512726}

third_party/WebKit/Source/platform/BUILD.gn

@@ -1736,7 +1736,6 @@ jumbo_source_set("blink_platform_unittests_sources") {
     "animation/CompositorFloatAnimationCurveTest.cpp",
     "animation/TimingFunctionTest.cpp",
     "audio/PushPullFIFOTest.cpp",
-    "audio/VectorMathTest.cpp",
     "bindings/RuntimeCallStatsTest.cpp",
     "exported/FilePathConversionTest.cpp",
     "exported/WebCORSPreflightResultCacheTest.cpp",