SPV 1.4: Add testing infrastructure for SPV 1.4 tests.

This includes the test for the first feature of OpEntryPoint.
diff --git a/gtests/AST.FromFile.cpp b/gtests/AST.FromFile.cpp
index b64b415..d4e7fb6 100644
--- a/gtests/AST.FromFile.cpp
+++ b/gtests/AST.FromFile.cpp
@@ -48,7 +48,7 @@
 TEST_P(CompileToAstTest, FromFile)
 {
     loadFileCompileAndCheck(GlobalTestSettings.testRoot, GetParam(),
-                            Source::GLSL, Semantics::OpenGL, glslang::EShTargetVulkan_1_0,
+                            Source::GLSL, Semantics::OpenGL, glslang::EShTargetVulkan_1_0, glslang::EShTargetSpv_1_0,
                             Target::AST);
 }
 
@@ -57,7 +57,7 @@
 TEST_P(CompileToAstTestNV, FromFile)
 {
     loadFileCompileAndCheck(GlobalTestSettings.testRoot, GetParam(),
-                            Source::GLSL, Semantics::OpenGL, glslang::EShTargetVulkan_1_0,
+                            Source::GLSL, Semantics::OpenGL, glslang::EShTargetVulkan_1_0, glslang::EShTargetSpv_1_0,
                             Target::AST);
 }
 #endif