GLSL: clean up GLSL output whitespace generation.

More line() and less std::endl.
More automated indents and less manual spacing.
Put a single newline after every struct and function declaration.

Note that this does touch every test result, but only affects whitespace.

Change-Id: I7506b9029b79b91fb335911dba44369b36f09bbe
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/78300
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Stephen White <senorblanco@chromium.org>

test/bug/fxc/vector_assignment_in_loop/loop_call_with_loop.wgsl.expected.glsl

@@ -5,7 +5,6 @@ vec2 v2f = vec2(0.0f, 0.0f);
 ivec3 v3i = ivec3(0, 0, 0);
 uvec4 v4u = uvec4(0u, 0u, 0u, 0u);
 bvec2 v2b = bvec2(false, false);
-
 void foo() {
   {
     for(int i = 0; (i < 2); i = (i + 1)) {
@@ -26,8 +25,8 @@ void tint_symbol() {
   }
   return;
 }
+
 void main() {
   tint_symbol();
 }
 
-

test/bug/fxc/vector_assignment_in_loop/loop_call_with_no_loop.wgsl.expected.glsl

@@ -5,7 +5,6 @@ vec2 v2f = vec2(0.0f, 0.0f);
 ivec3 v3i = ivec3(0, 0, 0);
 uvec4 v4u = uvec4(0u, 0u, 0u, 0u);
 bvec2 v2b = bvec2(false, false);
-
 void foo() {
   int i = 0;
   v2f[i] = 1.0f;
@@ -23,8 +22,8 @@ void tint_symbol() {
   }
   return;
 }
+
 void main() {
   tint_symbol();
 }
 
-

test/bug/fxc/vector_assignment_in_loop/loop_types_all.wgsl.expected.glsl

@@ -33,8 +33,8 @@ void tint_symbol() {
   }
   return;
 }
+
 void main() {
   tint_symbol();
 }
 
-

test/bug/fxc/vector_assignment_in_loop/loop_types_repeated.wgsl.expected.glsl

@@ -25,8 +25,8 @@ void tint_symbol() {
   }
   return;
 }
+
 void main() {
   tint_symbol();
 }
 
-

test/bug/fxc/vector_assignment_in_loop/loop_types_some.wgsl.expected.glsl

@@ -34,8 +34,8 @@ void tint_symbol() {
   v4b[i] = true;
   return;
 }
+
 void main() {
   tint_symbol();
 }
 
-

test/bug/fxc/vector_assignment_in_loop/no_loop.wgsl.expected.glsl

@@ -30,8 +30,8 @@ void tint_symbol() {
   v4b[i] = true;
   return;
 }
+
 void main() {
   tint_symbol();
 }
 
-