[tests] Run swift-(corelibs-)foundation tests in debug configuration on Windows

This should improve CI times because building in debug configuration instead of release configuration is significantly faster. Since we don’t install the build of swift-(corelibs-)foundation using SwiftPM into the toolchain, this doesn’t have any performance impact on users of the toolchain.

Author: ahoppen

utils/build.ps1

@@ -107,6 +107,9 @@ The memory allocator used in the toolchain binaries, if it's
 `mimalloc`, it uses mimalloc. Otherwise, it uses the default
 allocator.
 
+.PARAMETER FoundationTestConfiguration
+Whether to run swift-foundation and swift-corelibs-foundation tests in a debug or release configuration.
+
 .EXAMPLE
 PS> .\Build.ps1
 
@@ -142,6 +145,8 @@ param(
   [switch] $Clean,
   [switch] $DebugInfo,
   [switch] $EnableCaching,
+  [ValidateSet("debug", "release")]
+  [string] $FoundationTestConfiguration = "debug",
   [string] $Cache = "",
   [string] $Allocator = "",
   [switch] $Summary,
@@ -1234,6 +1239,7 @@ function Build-SPMProject {
     [string] $Src,
     [string] $Bin,
     [hashtable] $Arch,
+    [string] $Configuration = "release",
     [Parameter(ValueFromRemainingArguments)]
     [string[]] $AdditionalArguments
   )
@@ -1263,7 +1269,7 @@ function Build-SPMProject {
     $Arguments = @(
         "--scratch-path", $Bin,
         "--package-path", $Src,
-        "-c", "release",
+        "-c", $Configuration,
         "-Xbuild-tools-swiftc", "-I$SDKInstallRoot\usr\lib\swift",
         "-Xbuild-tools-swiftc", "-L$SDKInstallRoot\usr\lib\swift\windows",
         "-Xcc", "-I$SDKInstallRoot\usr\lib\swift",
@@ -1851,7 +1857,8 @@ function Build-Foundation([Platform]$Platform, $Arch, [switch]$Test = $false) {
         -Action Test `
         -Src $SourceCache\swift-foundation `
         -Bin $OutDir `
-        -Arch $HostArch
+        -Arch $HostArch `
+        -Configuration $FoundationTestConfiguration
     }
 
     $OutDir = Join-Path -Path $HostArch.BinaryCache -ChildPath foundation-tests
@@ -1869,7 +1876,8 @@ function Build-Foundation([Platform]$Platform, $Arch, [switch]$Test = $false) {
         -Action Test `
         -Src $SourceCache\swift-corelibs-foundation `
         -Bin $OutDir `
-        -Arch $HostArch
+        -Arch $HostArch `
+        -Configuration $FoundationTestConfiguration
     }
   } else {
     $DispatchBinaryCache = Get-TargetProjectBinaryCache $Arch Dispatch