tint: remove LoopToForLoop and FoldTrivialSingleUseLets transforms for HLSL and GLSL

Change-Id: I18c807b2449dc2842cb9dbfaeba98dae640d2355
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/102621
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>

test/tint/expressions/binary/bit-or/scalar-scalar/i32.wgsl.expected.dxc.hlsl

@@ -1,5 +1,7 @@
 [numthreads(1, 1, 1)]
 void f() {
-  const int r = 3;
+  const int a = 1;
+  const int b = 2;
+  const int r = (a | b);
   return;
 }

test/tint/expressions/binary/bit-or/scalar-scalar/i32.wgsl.expected.fxc.hlsl

@@ -1,5 +1,7 @@
 [numthreads(1, 1, 1)]
 void f() {
-  const int r = 3;
+  const int a = 1;
+  const int b = 2;
+  const int r = (a | b);
   return;
 }

test/tint/expressions/binary/bit-or/scalar-scalar/i32.wgsl.expected.glsl

@@ -1,7 +1,9 @@
 #version 310 es
 
 void f() {
-  int r = 3;
+  int a = 1;
+  int b = 2;
+  int r = (a | b);
 }
 
 layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;

test/tint/expressions/binary/bit-or/scalar-scalar/u32.wgsl.expected.dxc.hlsl

@@ -1,5 +1,7 @@
 [numthreads(1, 1, 1)]
 void f() {
-  const uint r = 3u;
+  const uint a = 1u;
+  const uint b = 2u;
+  const uint r = (a | b);
   return;
 }

test/tint/expressions/binary/bit-or/scalar-scalar/u32.wgsl.expected.fxc.hlsl

@@ -1,5 +1,7 @@
 [numthreads(1, 1, 1)]
 void f() {
-  const uint r = 3u;
+  const uint a = 1u;
+  const uint b = 2u;
+  const uint r = (a | b);
   return;
 }

test/tint/expressions/binary/bit-or/scalar-scalar/u32.wgsl.expected.glsl

@@ -1,7 +1,9 @@
 #version 310 es
 
 void f() {
-  uint r = 3u;
+  uint a = 1u;
+  uint b = 2u;
+  uint r = (a | b);
 }
 
 layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;