Revert "Point sdk/bin/dart to .../dart-sdk/bin/dart"

This reverts commit 0dd150b.

Reason for revert: need to run this by more people

Original change's description:
> Point sdk/bin/dart to .../dart-sdk/bin/dart
>
> Change-Id: I9ec75d2f4c8695448db922b57c2980715d6ef3f0
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/417702
> Commit-Queue: Samuel Rawlins <[email protected]>
> Reviewed-by: Samuel Rawlins <[email protected]>
> Auto-Submit: Mayank Patke <[email protected]>

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I6c5538a5fb03a1ffc49a0fd473308e1236a0235e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/417941
Auto-Submit: Mayank Patke <[email protected]>
Bot-Commit: Rubber Stamper <[email protected]>
Reviewed-by: Samuel Rawlins <[email protected]>
Commit-Queue: Rubber Stamper <[email protected]>

Author: fishythefish

sdk/bin/dart

@@ -53,4 +53,4 @@ fi
 
 BIN_DIR="$OUT_DIR$DART_CONFIGURATION"
 
-exec "$BIN_DIR"/dart-sdk/bin/dart "$@"
+exec "$BIN_DIR"/dart "$@"

sdk/bin/dart.bat

@@ -13,4 +13,4 @@ if "%DART_CONFIGURATION%"=="" set DART_CONFIGURATION=ReleaseX64
 
 set arguments=%*
 
-"%SCRIPTPATH%\..\..\out\%DART_CONFIGURATION%\dart-sdk\bin\dart.exe" %arguments%
+"%SCRIPTPATH%\..\..\out\%DART_CONFIGURATION%\dart.exe" %arguments%