Revert "Fix for loops with multiple init-variables in Metal."

This reverts commit a36fa6636b6b9ea46c572c541c54082d5e790432.

Reason for revert: http://review.skia.org/398221 instead

Original change's description:
> Fix for loops with multiple init-variables in Metal.
>
> This is structured differently than the GLSL fix, due to the different
> semantics of array-types in Metal.
>
> Change-Id: I27ad11539bbbb96abb0686d5686b8fcd2f5dd6d1
> Bug: skia:11860
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/396916
> Commit-Queue: John Stiles <johnstiles@google.com>
> Auto-Submit: John Stiles <johnstiles@google.com>
> Reviewed-by: Ethan Nicholas <ethannicholas@google.com>

Bug: skia:11860
Change-Id: I53a8132a72068bc9bff74ce1b2e69bc0618c106a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/398224
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
diff --git a/src/sksl/codegen/SkSLMetalCodeGenerator.cpp b/src/sksl/codegen/SkSLMetalCodeGenerator.cpp
index 9647907..cb6b81e 100644
--- a/src/sksl/codegen/SkSLMetalCodeGenerator.cpp
+++ b/src/sksl/codegen/SkSLMetalCodeGenerator.cpp
@@ -1876,26 +1876,12 @@
         return;
     }
 
-    bool closeForLoopScope = false;
+    this->write("for (");
     if (f.initializer() && !f.initializer()->isEmpty()) {
-        if (f.initializer()->is<Block>()) {
-            // Our initializer-statement could potentially contain multiple variables of differing
-            // type (e.g. `int` and `int[4]`). In Metal, there isn't a clean way to express this in
-            // the for's init-statement block, since we use `array<T, N>` type for our arrays.
-            // Instead, we synthesize a scope and declare those variables right above the for loop.
-            this->writeLine("{");
-            ++fIndentation;
-            this->writeStatement(*f.initializer());
-            this->write("for (; ");
-            closeForLoopScope = true;
-        } else {
-            this->write("for (");
-            this->writeStatement(*f.initializer());
-        }
+        this->writeStatement(*f.initializer());
     } else {
-        this->write("for (; ");
+        this->write("; ");
     }
-
     if (f.test()) {
         this->writeExpression(*f.test(), Precedence::kTopLevel);
     }
@@ -1905,12 +1891,6 @@
     }
     this->write(") ");
     this->writeStatement(*f.statement());
-
-    if (closeForLoopScope) {
-        --fIndentation;
-        this->writeLine("");
-        this->writeLine("}");
-    }
 }
 
 void MetalCodeGenerator::writeDoStatement(const DoStatement& d) {