Fix line number handling in line directive callback.

The line argument passed into the lineCallback function is the
literal value of the first argument of the #line directive.
lastLine in DoPreprocessing() should be updated taking into
consideration the different definitions for #line between specs.

Add a test to reveal the bug.

Test/baseResults/preprocessor.line.frag.err

@@ -0,0 +1,2 @@
+Warning, version 310 is not yet complete; most version-specific features are present, but some are missing.
+

Test/baseResults/preprocessor.line.frag.out

@@ -0,0 +1,6 @@
+#version 310 es
+
+#line 1 2
+#pragma something
+void main(){ }
+

Test/baseResults/preprocessor.line.vert.out

@@ -7,7 +7,6 @@
 #line 2
 
 #line 0
-
 #line 4
 
 #line 8

Test/preprocessor.line.frag

@@ -0,0 +1,4 @@
+#version 310 es
+#line 1 2
+#pragma something
+void main() {}

Test/test-preprocessor-list

@@ -3,5 +3,6 @@ preprocessor.errors.vert
 preprocessor.extensions.vert
 preprocessor.function_macro.vert
 preprocessor.line.vert
+preprocessor.line.frag
 preprocessor.pragma.vert
 preprocessor.simple.vert