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>
diff --git a/test/loops/loop.wgsl.expected.glsl b/test/loops/loop.wgsl.expected.glsl
index e0d9330..81b6873 100644
--- a/test/loops/loop.wgsl.expected.glsl
+++ b/test/loops/loop.wgsl.expected.glsl
@@ -5,12 +5,11 @@
 void unused_entry_point() {
   return;
 }
+
 void main() {
   unused_entry_point();
 }
 
-
-
 int f() {
   int i = 0;
   while (true) {
@@ -20,3 +19,4 @@
     }
   }
 }
+