Implement GL_EXT_terminate_invocation (#2454)

* Implement GL_EXT_terminate_invocation.

* terminateInvocation: declare the SPV extension

* Update test results for spirv-tools and bison version bumps

Co-authored-by: John Kessenich <cepheus@frii.com>

Test/terminate.vert

@@ -0,0 +1,10 @@
+#version 400
+
+void foo() { terminateInvocation; } // ERROR: identifier undeclared
+
+#extension GL_EXT_terminate_invocation : enable
+
+void main()
+{
+    terminateInvocation;  // ERROR: wrong stage
+}