Add Float16/Int8/Int16 capabilities for private variables and function parameters

Test/spv.functionParameterTypes.frag

@@ -0,0 +1,20 @@
+#version 460 core
+#extension GL_EXT_shader_explicit_arithmetic_types_int64 : enable
+#extension GL_EXT_shader_explicit_arithmetic_types_int8 : enable
+#extension GL_EXT_shader_explicit_arithmetic_types_int16 : enable
+#extension GL_EXT_shader_explicit_arithmetic_types_float16 : enable
+
+int f(int8_t i8,
+       uint8_t u8,
+       int16_t i16,
+       uint16_t u16,
+       int64_t i64,
+       uint64_t u64,
+       float16_t f16)
+{
+    return 0;
+}
+
+void main()
+{
+}