redefine _Float16 as __fp16 for x86[_64] to allow removing workaround from inhouse clang

At present, the tests might not actually use _Float16 (the generated
tests that are incorporated into the functional tests are built in
frameworks/ml rather than in hardware/interfaces); but the makefiles
are changed anyway, in case _Float16 is added in the future.

Bug: 138709788

Test: for (walleye, aosp_x86 [on emulator], aosp_x86_64 [on emulator])
        Use clang where _Float16 is disabled for x86[_64]
        $ cd $ANDROID_BUILD_TOP/neuralnetworks/1.0/vts/functional
        inspect build commands for tests as to whether or not
          expected options related to redefinition are present
        $ cd $ANDROID_BUILD_TOP/neuralnetworks/1.1/vts/functional
        inspect build commands for tests as to whether or not
          expected options related to redefinition are present

Change-Id: I9225b228947696d249771b3a35b1f82de9c26b6e

neuralnetworks/1.0/vts/functional/Android.bp

@@ -14,13 +14,30 @@
 // limitations under the License.
 //
 
+cc_defaults {
+    name: "neuralnetworks_vts_functional_defaults",
+    defaults: ["VtsHalTargetTestDefaults"],
+    arch: {
+        x86: {
+            cflags: [ "-D_Float16=__fp16",
+                      "-Xclang", "-fnative-half-type",
+                      "-Xclang", "-fallow-half-arguments-and-returns" ],
+        },
+        x86_64: {
+            cflags: [ "-D_Float16=__fp16",
+                      "-Xclang", "-fnative-half-type",
+                      "-Xclang", "-fallow-half-arguments-and-returns" ],
+        },
+    },
+}
+
 cc_library_static {
     name: "VtsHalNeuralNetworksV1_0_utils",
     srcs: [
         "Callbacks.cpp",
         "Utils.cpp",
     ],
-    defaults: ["VtsHalTargetTestDefaults"],
+    defaults: ["neuralnetworks_vts_functional_defaults"],
     export_include_dirs: ["include"],
     shared_libs: [
         "libfmq",
@@ -42,7 +59,7 @@ cc_library_static {
 
 cc_test {
     name: "VtsHalNeuralnetworksV1_0TargetTest",
-    defaults: ["VtsHalTargetTestDefaults"],
+    defaults: ["neuralnetworks_vts_functional_defaults"],
     srcs: [
         "BasicTests.cpp",
         "TestAssertions.cpp",

neuralnetworks/1.1/vts/functional/Android.bp

@@ -16,7 +16,7 @@
 
 cc_test {
     name: "VtsHalNeuralnetworksV1_1TargetTest",
-    defaults: ["VtsHalTargetTestDefaults"],
+    defaults: ["neuralnetworks_vts_functional_defaults"],
     srcs: [
         "BasicTests.cpp",
         "TestAssertions.cpp",

neuralnetworks/1.2/vts/functional/Android.bp

@@ -16,7 +16,7 @@
 
 cc_library_static {
     name: "VtsHalNeuralNetworksV1_2Callbacks",
-    defaults: ["VtsHalTargetTestDefaults"],
+    defaults: ["neuralnetworks_vts_functional_defaults"],
     export_include_dirs: ["include"],
     srcs: [
         "Callbacks.cpp",
@@ -33,7 +33,7 @@ cc_library_static {
 
 cc_test {
     name: "VtsHalNeuralnetworksV1_2TargetTest",
-    defaults: ["VtsHalTargetTestDefaults"],
+    defaults: ["neuralnetworks_vts_functional_defaults"],
     srcs: [
         "BasicTests.cpp",
         "CompilationCachingTests.cpp",

neuralnetworks/1.3/vts/functional/Android.bp

@@ -16,7 +16,7 @@
 
 cc_library_static {
     name: "VtsHalNeuralNetworksV1_3_utils",
-    defaults: ["VtsHalTargetTestDefaults"],
+    defaults: ["neuralnetworks_vts_functional_defaults"],
     export_include_dirs: ["include"],
     srcs: [
         "Callbacks.cpp",
@@ -35,7 +35,7 @@ cc_library_static {
 
 cc_test {
     name: "VtsHalNeuralnetworksV1_3TargetTest",
-    defaults: ["VtsHalTargetTestDefaults"],
+    defaults: ["neuralnetworks_vts_functional_defaults"],
     srcs: [
         "BasicTests.cpp",
         "CompilationCachingTests.cpp",