Add support for ES31 context creation

The dEQP test for context creation passes.

SH_WEBGL3_SPEC has been added, but it should be considered whether we
should keep it, remove it or rename it. It was added so that there is
a webgl mapping to es 310 shaders. Check Compiler.cpp. The bison file
has been modified so that some tokens from es3 can be also used in
es31 as well.

A separate macro ES3_1_ONLY is added so that some tokens are limited
only for es 310 shaders.

BUG=angleproject:1442
TEST=angle_unittests

Change-Id: I2e5ca227c96046c30dc796ab934f3fda9c533eba
Reviewed-on: https://chromium-review.googlesource.com/360300
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/tests/gl_tests/BlendMinMaxTest.cpp b/src/tests/gl_tests/BlendMinMaxTest.cpp
index ef1ba26..5b1035c 100644
--- a/src/tests/gl_tests/BlendMinMaxTest.cpp
+++ b/src/tests/gl_tests/BlendMinMaxTest.cpp
@@ -38,7 +38,7 @@
 
     void runTest(GLenum colorFormat)
     {
-        if (getClientVersion() < 3 && !extensionEnabled("GL_EXT_blend_minmax"))
+        if (getClientMajorVersion() < 3 && !extensionEnabled("GL_EXT_blend_minmax"))
         {
             std::cout << "Test skipped because ES3 or GL_EXT_blend_minmax is not available." << std::endl;
             return;
@@ -166,7 +166,7 @@
 
 TEST_P(BlendMinMaxTest, RGBA32f)
 {
-    if (getClientVersion() < 3 || !extensionEnabled("GL_EXT_color_buffer_float"))
+    if (getClientMajorVersion() < 3 || !extensionEnabled("GL_EXT_color_buffer_float"))
     {
         std::cout << "Test skipped because ES3 and GL_EXT_color_buffer_float are not available."
                   << std::endl;
@@ -192,7 +192,7 @@
 
 TEST_P(BlendMinMaxTest, RGBA16F)
 {
-    if (getClientVersion() < 3 && !extensionEnabled("GL_EXT_color_buffer_half_float"))
+    if (getClientMajorVersion() < 3 && !extensionEnabled("GL_EXT_color_buffer_half_float"))
     {
         std::cout << "Test skipped because ES3 or GL_EXT_color_buffer_half_float is not available."
                   << std::endl;