Remove hardcoded sdk_versions in third_party

It seems like the sdk_version partially controls which
libc++ is used during compilation. This causes mismatches
when some targets specify a version and some targets do not.

Bug: b/138239233
Bug: b/142276229
Test: built locally
Change-Id: Idd4ede2fd3c162dd0edd850155daff70b2c05bd2
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/37168
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Tested-by: Jason Macnak <natsu@google.com>
diff --git a/third_party/SPIRV-Tools/Android.bp b/third_party/SPIRV-Tools/Android.bp
index e3eab69..6a10a28 100644
--- a/third_party/SPIRV-Tools/Android.bp
+++ b/third_party/SPIRV-Tools/Android.bp
@@ -217,7 +217,6 @@
 cc_library_static {
     name: "swiftshader_spirv-tools",
     vendor_available: true,
-    sdk_version: "27",
     srcs: [
         "source/*.cpp",
         "source/util/*.cpp",
diff --git a/third_party/marl/Android.bp b/third_party/marl/Android.bp
index 9f45246..1c0cef8 100644
--- a/third_party/marl/Android.bp
+++ b/third_party/marl/Android.bp
@@ -17,7 +17,6 @@
 cc_library_static {
     name: "swiftshader_marl",
     vendor_available: true,
-    sdk_version: "27",
     srcs: [
         "src/debug.cpp",
         "src/memory.cpp",